Flanged interbody fusion device with fastener insert and retaining ring

ABSTRACT

Methods and devices are disclosed for treating the vertebral column. An integrated fixation plate and spacer having a retaining structure within the screw holes of the fixation plate to resist backout of screws attaching the fixation plate to the bone is provided. A movable joint may be provided between the fixation plate and spacer. In some embodiments, a screw hole insert is also provided to resist shear forces acting between the screw and fixation plate. In some embodiments, an integrated fixation plate and spacer system is provided, comprising two or more integrated fixation plate and spacer implants, wherein the fixation plates of each implant has a complementary configuration to allow attachment of the implants at adjacent intervertebral spaces. Alternative fixation systems are also contemplated.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/318,421, filed Jun. 27, 2014, which is a continuation ofU.S. patent application Ser. No. 13/901,327, filed May 23, 2013, whichis a continuation of U.S. patent application Ser. No. 11/374,462, filedMar. 13, 2006, which claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Application No. 60/662,747 filed on Mar. 17, 2005 and U.S.Provisional Application No. 60/708,918 filed on Aug. 17, 2005. U.S.patent Ser. No. 11/374,462, filed Mar. 13, 2006, U.S. ProvisionalApplication No. 60/662,747 filed on Mar. 17, 2005 and U.S. ProvisionalApplication No. 60/708,918 filed on Aug. 17, 2005 are herebyincorporated by reference in their entirety under 37 CFR 1.57.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to systems and methods for performingspinal fixation. The invention comprises one or more vertebral spacersthat feature an attachment system that resists backing out of the screwsused to attach the spacers to the vertebrae. The invention may beconfigured so that multiple adjacent spacers may be used along thevertebral column.

Description of the Related Art

Advancing age, as well as injury, can lead to degenerative changes inthe bones, discs, joints and ligaments of the spine, producing pain andinstability. Under certain circumstances, alleviation of the problemscan be provided by performing spinal fusion. Spinal fusion is a surgicaltechnique where two or more vertebrae of the spinal column are fusedtogether to eliminate the motion between the fused vertebrae. Spinalfusion is used to treat conditions where the spine exhibits instability.Spine instability may result from causes such as fracture, scoliosis andspondylolisthesis, where one or more vertebrae move in a forwarddirection relative to the other vertebrae. Spinal fusion with discectomyis also performed for herniations of the discs. This surgery involvesremoval of the affected disc and fusion of the adjacent vertebrae.Traditionally, bone grafts have been used to fuse the vertebrae, butvarious types of vertebral implants have also been used.

The use of bone plate and bone screw fixation systems for treatinginjuries to bones is well established. In most instances, a bone plateis positioned over and surrounding the bone injury area and secured tothe bone. The bone plate is secured to the bone by bone screws or othersimilar fasteners inserted through holes in the bone plate and into thebone itself. The screws are tightened so that the bone plate holds thebone to be treated in place in order to insure proper healing. Earlyfixation devices tended to be applicable only to long bone injuries withonly limited uses for lower lumbar spinal injuries and disorders. Theuse of plate/screw fixation systems later expanded, however, to includemore uses for spinal injuries, including fusion of vertebrae includingfixation devices for treating cervical vertebrae injuries.

Notwithstanding the foregoing, there remains a need for improved methodsand devices for treating spinal instability.

SUMMARY OF THE INVENTION

Methods and devices are disclosed for treating the vertebral column. Anintegrated fixation plate and spacer having a retaining structure withinthe screw holes of the fixation plate to resist backout of screwsattaching the fixation plate to the bone is provided. In someembodiments, a screw hole insert is also provided to resist shear forcesacting between the screw and fixation plate. In some embodiments, anintegrated fixation plate and spacer system is provided, comprising twoor more integrated fixation plate and spacer implants, wherein thefixation plates of each implant has a complementary configuration toallow attachment of the implants at adjacent intervertebral spaces.Alternative fixation systems are also contemplated.

In one embodiment of the invention, an intervertebral stabilizationsystem is provided, comprising a first stabilization plate integratedwith a first spacer, wherein the first stabilization plate has an upperportion and a lower portion and a second stabilization plate integratedwith a second spacer, wherein the second stabilization plate has anupper portion and a lower portion, wherein the lower portion of thefirst stabilization plate has a configuration complementary to theconfiguration of the upper portion of the second stabilization plate. Insome embodiments, the configuration of the lower portion of the secondstabilization plate is complementary to the configuration of the upperportion of the second stabilization plate. In some embodiments, thelower portion of the second stabilization plate has a relative shapeequal to the relative shape of the upper portion of the secondstabilization plate rotated 180 degrees. In one embodiment, the upperportion of the first stabilization plate may comprise two attachmentholes and the lower portion of the first stabilization plate maycomprise one attachment hole. The intervertebral stabilization systemmay further comprise a third stabilization plate and a third spacer,wherein the configuration of the upper portion of the thirdstabilization plate is complementary to the configuration of the lowerportion of the second stabilization plate. The third stabilization platemay be integrated with the third spacer. The lower portion of the thirdstabilization plate may have a configuration complementary to theconfiguration of the upper portion of the third stabilization plate. Thelower portion of the third stabilization plate may have a relative shapeequal to the relative shape of the upper portion of the thirdstabilization plate rotated 180 degrees. In another embodiment, theintervertebral stabilization system may also further comprise a fourthstabilization plate and a fourth spacer, wherein the upper portion ofthe fourth stabilization plate has a configuration complementary toconfiguration of the lower portion of the third stabilization plate. Inthis embodiment, the second stabilization plate and third stabilizationplate may have the same configuration. The lower portion of the secondstabilization plate may have a relative shape equal to the relativeshape of the upper portion of the second stabilization plate rotated 180degrees. In one embodiment, the lower portion of the first stabilizationplate has a right-sided complementary shape and the upper portion of thesecond stabilization plate has a left-sided complementary shape. Inanother embodiment, the lower portion of the first stabilization platehas a left-sided complementary shape and the upper portion of the secondstabilization plate has a right-sided complementary shape. The lowerportion of the second stabilization plate may have a right-sidedcomplementary shape. The lower portion of the second stabilization platemay have a left-sided complementary shape. The lower portion of thefirst stabilization plate may have an inside complementary shape and theupper portion of the second stabilization plate has an outsidecomplementary shape. The lower portion of the first stabilization platemay have an underside complementary shape and the upper portion of thesecond stabilization plate has a topside complementary shape.

In another embodiment of the invention, an implant for treating thespine is provided, comprising a stabilization plate having an accesssurface and a bone facing surface, an upper portion and a lower portion,a spacer integrated with the stabilization plate at the bone facingsurface, a first attachment lumen between the access surface and thebone facing surface of the stabilization plate, the lumen having a firstattachment diameter adjacent to the access surface of the stabilizationplate, a lumen surface and a second attachment diameter adjacent to thebone facing surface of the stabilization plate, a retaining channelalong the lumen surface, and a third attachment diameter about theretaining channel, wherein the first attachment diameter is greater thanthe second attachment diameter, a deformable retaining ring at leastpartially located within the retaining channel, and a first attachmentlumen insert having an inner insert diameter and an outer insertdiameter. The at least a portion of the spacer may comprise tissueengagement structures. The tissue engagement structures may compriseteeth. The implant may further comprise a bone screw, the bone screwhaving a screw head and a screw body, wherein the screw head has a headdiameter less than the first attachment diameter and greater than thesecond attachment diameter, or a head diameter less than the firstattachment diameter and greater than the inner insert diameter. Theimplant may further comprise a second attachment lumen between theaccess surface and the bone facing surface of the stabilization plate,the lumen having a fourth attachment diameter adjacent to the accesssurface of the stabilization plate, a lumen surface and a fifthattachment diameter adjacent to the bone facing surface of thestabilization plate.

In another embodiment, a method for treating a spine is provided,comprising the steps of providing a first stabilization plate integratedwith a first spacer, wherein the first stabilization plate comprises anupper portion, a lower portion and a plurality of attachment holes, atleast one attachment hole comprising a retaining structure and anattachment insert, inserting the spacer component into a vertebral spacebetween a first vertebra and a second vertebra, attaching the upperportion of the first stabilization plate to the first vertebra, andattaching the lower portion of the first stabilization plate to thesecond vertebra.

In one embodiment of the invention, a method for treating a spine isprovided comprising the steps of providing an integrated stabilizationplate and spacer system, comprising a first integrated stabilizationplate and first spacer and a second integrated stabilization plate and asecond spacer, each stabilization plate having an upper portion and alower portion and wherein the lower portion of the first integratedstabilization plate has a complementary shape to the upper portion ofthe second integrated stabilization plate, inserting the first spacerinto a first intervertebral space between a first vertebra and a secondvertebra, attaching the upper portion of the first integratedstabilization plate to the first vertebra, attaching the lower portionof the first integrated stabilization plate to the second vertebra,inserting the second spacer into a second intervertebral space betweenthe second vertebra and a third vertebra, wherein the secondintervertebral space is next to the first intervertebral space along avertebral column, attaching the upper portion of the second integratedstabilization plate to the second vertebra; and attaching the lowerportion of the second integrated stabilization plate to the thirdvertebra. In some instances, the integrated stabilization plate andspacer system of the providing step may further comprise a thirdintegrated stabilization plate and a second spacer, wherein the lowerportion of the second integrated stabilization plate has a complementaryshape to the upper portion of the third integrated stabilization plate.The method for treating a spine may further comprise the steps ofinserting the third spacer into a third intervertebral space between thethird vertebra and a fourth vertebra, wherein the third intervertebralspace is next to the second intervertebral space along the vertebralcolumn, attaching the upper portion of the third integratedstabilization plate to the third vertebra, and attaching the lowerportion of the third integrated stabilization plate to the fourthvertebra.

In one embodiment of the invention, an orthopedic implant assembly isprovided, comprising a stabilizing element having a trailing surface, aleading surface and at least one lumen, the lumen having a first openingat the trailing surface, a second opening at the leading surface that issmaller than the first opening, and a passageway extending from thefirst opening to the second opening, a securing element having anelongated body, a head at one end of the body and integral therewith,and a lumen insert member defining a portion of the passageway, havingan inner diameter and an outer diameter, and adapted to substantiallyreduce any force exerted between the stabilizing element and thesecuring element, wherein the diameter of the head of the securingelement is greater than the lesser diameter between the second openingof the lumen and the inner diameter of the insert. The orthopedicimplant may further comprise an interbody element integral with theleading surface of the stabilizing element and/or a locking assembly forresisting movement of securing element in at least one direction.

In another embodiment, an implant for treating the spine is provided,comprising: a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion; a spacer; and a moveableconnection between the spacer and the bone facing surface of thefixation plate. The moveable connection may be a hinge joint, a ball andsocket joint, or a metal cord attached between the spacer and the bonefacing surface of the fixation plate.

In one embodiment, an implant for treating the spine is provided,comprising: a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion; a spacer connected to thebone facing surface of the fixation plate; and one or more lockingplates with an alignment structure to non-frictionally resist rotationof the locking plate when partially attached to the fixation plate by afastener.

In another embodiment, an implant for treating the spine is provided,comprising: a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion; a spacer connected to thefixation plate at the bone facing surface; a first attachment lumenbetween the access surface and the bone facing surface of thestabilization plate, the lumen having a first attachment diameteradjacent to the access surface of the stabilization plate, a lumensurface and a second attachment diameter adjacent to the bone facingsurface of the stabilization plate, a retaining channel along the lumensurface, and a third attachment diameter about the retaining channel,wherein the first attachment diameter is greater than the secondattachment diameter; and a deformable retaining ring having a retainingsegment and a polyaxial segment and an abutting surface therebetween,wherein the retaining segment of the deformable retaining ring is atleast partially located within the retaining channel.

In one embodiment, a system for attaching to a structure is provided,comprising: an attachment device having an access surface, an facingsurface, a first attachment lumen between the access surface and thefacing surface of the attachment device, the first attachment lumenhaving a first attachment diameter adjacent to the access surface of theattachment device, a first lumen surface and a second attachmentdiameter adjacent to the facing surface of the attachment device, afirst retaining channel along the first lumen surface, and a thirdattachment diameter about the first retaining channel, wherein the firstattachment diameter is greater than the second attachment diameter; anda side-biased blocking structure at least partially within the retainingchannel having an uncompressed configuration that protrudes into thefirst attachment lumen and a compressed configuration that does notprotrude into the first attachment lumen. The blocking structure maycomprise a sloped surface.

In another embodiment of the invention, a fastener is provided,comprising: a fastener head and fastener shaft, the fastener headcomprising a screw lumen, an external groove and one or more openingsbetween the screw lumen and external groove, and an expandable memberlocated at least partially in the external groove and protruding throughthe one or more openings into the screw lumen. The expandable member maybe a ring. The fastener may further comprise a secondary screwconfigured for the screw lumen.

In one embodiment, an intervertebral stabilization system is provided,comprising a first stabilization plate integrated with a first spacer,wherein the first stabilization plate comprises an upper portion and alower portion, and a second stabilization plate integrated with a secondspacer, wherein the second stabilization plate comprises an upperportion and a lower portion, wherein the lower portion of the firststabilization plate has a configuration complementary to theconfiguration of the upper portion of the second stabilization plate.The configuration of the lower portion of the second stabilization platemay be complementary to the configuration of the upper portion of thesecond stabilization plate. The lower portion of the secondstabilization plate may have a relative shape equal to the relativeshape of the upper portion of the second stabilization plate rotated 180degrees. The upper portion of the first stabilization plate may comprisetwo attachment holes. The lower portion of the first stabilization platemay comprise one attachment hole. The intervertebral stabilizationsystem may further comprise a third stabilization plate and a thirdspacer, wherein the configuration of the upper portion of the thirdstabilization plate may be complementary to the configuration of thelower portion of the second stabilization plate. The third stabilizationplate may be integrated with the third spacer. The lower portion of thethird stabilization plate may have a configuration complementary to theconfiguration of the upper portion of the third stabilization plate. Thelower portion of the third stabilization plate may have a relative shapeequal to the relative shape of the upper portion of the thirdstabilization plate rotated 180 degrees. The intervertebralstabilization system may further comprise a fourth stabilization plateand a fourth spacer, wherein the upper portion of the fourthstabilization plate has a configuration complementary to configurationof the lower portion of the third stabilization plate. The secondstabilization plate and third stabilization plate may have the sameconfiguration. The lower portion of the second stabilization plate mayhave a relative shape equal to the relative shape of the upper portionof the second stabilization plate rotated 180 degrees. The lower portionof the first stabilization plate may have a right-sided complementaryshape and the upper portion of the second stabilization plate may have aleft-sided complementary shape. The lower portion of the firststabilization plate may have a left-sided complementary shape and theupper portion of the second stabilization plate may have a right-sidedcomplementary shape. The lower portion of the second stabilization platemay have a right-sided complementary shape. The lower portion of thesecond stabilization plate may have a left-sided complementary shape.The lower portion of the first stabilization plate may have an insidecomplementary shape and the upper portion of the second stabilizationplate may have an outside complementary shape. The lower portion of thefirst stabilization plate may have an underside complementary shape andthe upper portion of the second stabilization plate may have a topsidecomplementary shape.

In another embodiment, an orthopedic implant assembly is provided,comprising a stabilizing element having a trailing surface, a leadingsurface and at least one lumen, the lumen having a first opening at thetrailing surface, a second opening at the leading surface that may besmaller than the first opening, and a passageway extending from thefirst opening to the second opening, a securing element having anelongated body, a head at one end of the body and integral therewith,and a lumen insert member within a portion of the passageway, the lumeninsert member comprising an inner diameter and an outer diameter, andadapted to substantially reduce any force exerted between thestabilizing element and the securing element, wherein the diameter ofthe head of the securing element may be greater than the lesser diameterbetween the second opening of the lumen and the inner diameter of theinsert. The orthopedic implant assembly may further comprise aninterbody element integral with the leading surface of the stabilizingelement. The orthopedic implant assembly may further comprise a lockingassembly for resisting movement of securing element in at least onedirection.

In one embodiment, a method for treating a spine is provided, comprisingproviding an integrated stabilization plate and spacer system,comprising a first integrated stabilization plate and first spacer and asecond integrated stabilization plate and a second spacer, wherein eachstabilization plate having an upper portion and a lower portion andwherein the lower portion of the first integrated stabilization platemay have a complementary shape to the upper portion of the secondintegrated stabilization plate, inserting the first spacer into a firstintervertebral space between a first vertebra and a second vertebra,attaching the upper portion of the first integrated stabilization plateto the first vertebra, attaching the lower portion of the firstintegrated stabilization plate to the second vertebra, inserting thesecond spacer into a second intervertebral space between the secondvertebra and a third vertebra, wherein the second intervertebral spacemay be next to the first intervertebral space along a vertebral column,attaching the upper portion of the second integrated stabilization plateto the second vertebra, and attaching the lower portion of the secondintegrated stabilization plate to the third vertebra. The integratedstabilization plate and spacer system wherein providing the integratedstabilization plate and spacer system may further comprise a thirdintegrated stabilization plate and a second spacer, wherein the lowerportion of the second integrated stabilization plate may have acomplementary shape to the upper portion of the third integratedstabilization plate. The method for treating a spine may furthercomprise inserting the third spacer into a third intervertebral spacebetween the third vertebra and a fourth vertebra, wherein the thirdintervertebral space may be next to the second intervertebral spacealong the vertebral column, attaching the upper portion of the thirdintegrated stabilization plate to the third vertebra, and attaching thelower portion of the third integrated stabilization plate to the fourthvertebra.

In one embodiment, an implant for treating the spine is provided,comprising, a stabilization plate comprising an access surface and abone facing surface, an upper portion and a lower portion, a spacerintegral with the stabilization plate at the bone facing surface, afirst attachment lumen between the access surface and the bone facingsurface of the stabilization plate, the first attachment lumen having afirst attachment diameter adjacent to the access surface of thestabilization plate, a lumen surface and a second attachment diameteradjacent to the bone facing surface of the stabilization plate, aretaining channel along the lumen surface, and a third attachmentdiameter about the retaining channel, wherein the first attachmentdiameter may be greater than the second attachment diameter, adeformable retaining ring at least partially located within theretaining channel, and a first attachment lumen insert located at leastpartially in the first attachment lumen and having an inner insertdiameter and an outer insert diameter. At least a portion of the spacermay comprise tissue engagement structures. The tissue engagementstructures may comprise teeth. The implant may further comprise a bonescrew, the bone screw having a screw head and a screw body, wherein thescrew head may have a head diameter less than the first attachmentdiameter and greater than the second attachment diameter. The implantmay further comprise a bone screw, the bone screw having a screw headand a screw body, wherein the screw head may have a head diameter lessthan the first attachment diameter and greater than the inner insertdiameter. The outer insert diameter may be greater than the secondattachment diameter and the inner insert diameter may be smaller thanthe second attachment diameter. The second attachment diameter and thethird attachment diameter are generally equal. The first attachmentlumen insert may be located within the first attachment lumen. The firstattachment lumen insert may comprise an inner concave surface. The screwhead of the bone screw may comprise an outer convex surface. The outerconvex surface of the screw head may be complementary to the innerconcave surface of the first attachment lumen insert. The implant mayfurther comprise a second attachment lumen between the access surfaceand the bone facing surface of the stabilization plate, the secondattachment lumen having a fourth attachment diameter adjacent to theaccess surface of the stabilization plate, a lumen surface and a fifthattachment diameter adjacent to the bone facing surface of thestabilization plate.

In another embodiment, a method for treating a spine is provided,comprising providing a first stabilization plate integral with a firstspacer, wherein the first stabilization plate comprises an upperportion, a lower portion and a plurality of attachment holes, wherein atleast one attachment hole comprising a retaining structure and anattachment insert, inserting the first spacer into a vertebral spacebetween a first vertebra and a second vertebra, attaching the upperportion of the first stabilization plate to the first vertebra, andattaching the lower portion of the first stabilization plate to thesecond vertebra. The at least one attachment hole may further comprise aretaining groove and the retaining structure may be a retaining ringpositioned in the retaining groove. The attachment insert may comprise aconcave surface. The retaining ring may be integral with the attachmentinsert. Attaching the upper portion of the first stabilization plate tothe first vertebra may comprise inserting a bone fastener through one ofthe plurality of attachment holes located in the upper portion of thefirst stabilization plate and engaging the first vertebra with the bonefastener. The method may further comprise providing a secondstabilization plate integral with a second spacer, wherein the secondstabilization plate may comprise an upper portion and a lower portion.The lower portion of the first stabilization plate may have acomplementary configuration to the upper portion of the secondstabilization plate. The method may further comprise inserting thesecond spacer into a vertebral space between the second vertebra and athird vertebra.

In one embodiment, an implant for treating the spine is provided,comprising a fixation plate comprising an access surface and a bonefacing surface, an upper portion and a lower portion, a spacer connectedto the fixation plate at the bone facing surface, a first attachmentlumen between the access surface and the bone facing surface of thestabilization plate, the lumen having a first attachment diameteradjacent to the access surface of the stabilization plate, a lumensurface and a second attachment diameter adjacent to the bone facingsurface of the stabilization plate, a retaining channel along the lumensurface, and a third attachment diameter about the retaining channel,wherein the first attachment diameter may be greater than the secondattachment diameter, a deformable retaining ring having a retainingsegment and a polyaxial segment and an abutting surface therebetween,wherein the retaining segment of the deformable retaining ring may be atleast partially located within the retaining channel.

In another embodiment, an implant for treating the spine is provided,comprising a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion, a spacer, and anon-detachable articulation between the spacer and the bone facingsurface of the fixation plate. The non-detachable articulation may be ahinge joint. The hinge joint may have a joint axis that does notintersect the fixation plate. The hinge joint may have a joint axisconfigured to be generally perpendicular to a longitudinal axis of avertebral column when implanted. The hinge joint may have a joint axisconfigured to be generally parallel to a longitudinal axis of avertebral column when implanted. The non-detachable articulation may bea ball and socket joint. The non-detachable articulation may comprise ametal cord attached between the spacer and the bone facing surface ofthe fixation plate. The non-detachable articulation may be a pivotingarticulation.

In one embodiment, an implant for treating the spine is provided,comprising a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion, a spacer, and a pivotingarticulation between the spacer and the bone facing surface of thefixation plate. The pivoting articulation may be a hinge joint. Thehinge joint may have a joint axis configured to be generallyperpendicular to a longitudinal axis of a vertebral column whenimplanted. The hinge joint may have a joint axis configured to begenerally parallel to a longitudinal axis of a vertebral column whenimplanted. The pivoting articulation may be a ball and socket joint. Thepivoting articulation may comprise a metal cord attached between thespacer and the bone facing surface of the fixation plate. The pivotingarticulation may be a detachable articulation.

In another embodiment, an implant for treating the spine is provided,comprising a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion, a spacer, and a rotatablearticulation between the spacer and the fixation plate and comprising anaxis of rotation, wherein the axis of rotation of the rotatablearticulation does not intersect the fixation plate. The axis of rotationof the rotatable articulation may be generally parallel to the fixationplate. The rotatable articulation may be configured to allow reversibleseparation of the fixation plate and spacer.

In another embodiment, an implant for treating the spine is provided,comprising a fixation plate comprising an access surface and a bonefacing surface, an upper portion, a lower portion, and at least oneattachment lumen between the access surface and the bone facing surface,a spacer connected to the bone facing surface of the fixation plate, anda locking plate configured to overlie the at least one attachment lumenand comprising an alignment structure to non-frictionally resistrotation of the locking plate when the locking plate is partiallyattached to the fixation plate by a fastener. The implant may furthercomprise two attachment lumens and the locking plate may overlie atleast one of the two attachment lumens. The locking plate may overlieboth of the two attachment lumens. The fixation plate may furthercomprise a third attachment lumen. The locking plate may overlie the twoattachment lumens and the third attachment lumen. The fixation plate mayfurther comprise a fourth attachment lumen. The locking plate mayoverlie the two attachment lumens, the third attachment lumen and thefourth attachment lumen. At least a portion of the spacer may comprisetissue engagement structures. The tissue engagement structures maycomprise teeth. The spacer may be integral with the bone facing surfaceof the fixation plate or may be connected to the bone facing surface ofthe fixation plate by an articulation joint. The articulation joint maybe separable or non-separable. The lower portion of the fixation platemay have a configuration complementary to the configuration of the upperportion of the fixation plate. The alignment structure may comprise anelongate member and wherein the fixation plate may further comprise analignment lumen configured to accept the elongate member. The elongatemember and the alignment lumen may be configured to resist rotation ofthe elongate member when in the alignment lumen. The locking plate mayhave an X-shaped configuration or an H-shaped configuration. The lockingplate may further comprise a second alignment structure and wherein thefixation plate may further comprise a second alignment lumen configuredfor accepting the second alignment structure. The locking plate mayoverlie one of the two attachment lumens and the implant may furthercomprise a second locking plate overlying the other of the twoattachment lumens.

In another embodiment, an implant for treating the spine is provided,comprising a flanged intervertebral spacer comprising a spacer body anda flange section, the flange section comprising an access surface and abone facing surface, an upper portion, a lower portion, four attachmentlumens between the access surface and the bone facing surface and twoalignment lumens, a locking plate comprising four attachment coversections and two alignment pins, wherein the four attachment coversections are configured to cover the four attachment lumens of theflange section and the two alignment pins are configured for insertioninto the two alignment lumens of the flange section.

In one embodiment, a system for attaching to a structure is provided,comprising an attachment device having an access surface, a facingsurface, a first attachment lumen between the access surface and thefacing surface of the attachment device, the first attachment lumenhaving a first attachment diameter adjacent to the access surface of theattachment device, a first lumen surface and a second attachmentdiameter adjacent to the facing surface of the attachment device, afirst retaining channel along the first lumen surface, and a thirdattachment diameter about the first retaining channel, wherein the firstattachment diameter may be greater than the second attachment diameter,and a side-biased blocking structure at least partially within theretaining channel and comprising an uncompressed configuration thatprotrudes into the first attachment lumen and a compressed configurationthat does not protrude into the first attachment lumen. The blockingstructure may comprise a slope surface. The blocking structure may be anarcuate structure. The arcuate structure may be a ring structure. Theblocking structure may be a rectangular plate with a through lumen. Thethrough lumen may be a circular through lumen. The attachment structuremay be an interbody spacer, a flanged interbody spacer, a fixation platea vertebral fixation plate, or an anterior cervical fixation plate. Theblocking structure may comprise a helical spring member, a leaf springmember, or an elongate bias member. The blocking structure may comprisea second elongate bias member. The elongate bias member may have anarcuate shape.

In one embodiment, a method for treating the spine is provided,comprising providing an orthopedic device comprising a fastener lumen, asecuring structure space about the fastener lumen, a securing structurein the fastener lumen and the securing structure space, wherein thesecuring structure may comprise a bias element and a non-deformableblocking element, inserting a fastener into the fastener lumen,displacing at least a portion of the non-deformable blocking elementfrom the fastener lumen into the securing structure space by compressingthe bias element, and passing the head of the fastener past thenon-deformable blocking element to allow re-expansion of the biaselement.

In another embodiment, a method for treating the spine is provided,comprising providing an orthopedic device comprising a fastener lumenwith a longitudinal lumen axis, a securing structure space about thefastener lumen, a securing structure in the fastener lumen and thesecuring structure space, wherein the securing structure may comprise abiased lumen blocker, inserting a fastener into the fastener lumen,eccentrically displacing the biased lumen blocker with respect to thelongitudinal axis of the fastener lumen, and passing the fastener pastbiased lumen blocker to allow reversion of the biased lumen blockertoward a prior position. The method may further comprise reverting thebiased lumen blocker toward a prior position or to a prior position.

In one embodiment, a fastener is provided, comprising a fastener headand fastener shaft, the fastener head comprising a screw lumen, anexternal groove and one or more openings between the screw lumen andexternal groove, and an expandable member located at least partially inthe external groove and protruding through the one or more openings intothe screw lumen. The expandable member may be a ring. The fastener mayfurther comprise a secondary screw configured for the screw lumen.

In one embodiment, an orthopedic fastening system is provided,comprising a fastener comprising a fastener head and a threaded fastenerbody, wherein the fastener head may comprise a lumen opening, a centralinternal lumen contiguous with the lumen opening, a side lumencontiguous with the central internal lumen and an expansion memberlocated at least partially within the side lumen and having an expandedconfiguration and a reduced configuration. The fastener head may furthercomprise an internal screw and located in the central internal lumen,the internal screw having a proximal position and a distal position. Theinternal screw in the proximal position may be located about the sidelumen and in the distal position may be located distal to the sidelumen. The proximal position of the internal screw may displace theexpansion member into the expanded configuration. The orthopedicproximal position of the internal screw at least partially displaces theexpansion member out of the side lumen. The proximal position of theinternal screw allows the expansion member to be in the reducedconfiguration. The expansion member in the reduced configuration may bepartially located in the central internal lumen. The proximal positionof the internal screw at least partially displaces the expansion memberout of the central internal lumen. The expansion member biased to thereduced configuration. The fastener head may further comprise anexpansion groove contiguous with the side lumen and the expansion membermay comprise an elongate body positioned about the expansion groove. Theelongate body may be an arcuate elongate body. The expansion member mayfurther comprise a radial elongate body located at least partially inthe side lumen. The orthopedic fastening system may further comprise anorthopedic device comprising a fastener lumen adapted to retain thefastener. The fastener lumen may comprise a proximal diameter, a middlediameter and a distal diameter, wherein the proximal diameter is smallerthan the middle diameter. The distal diameter of the fastener lumen maybe smaller than the proximal diameter of the fastener lumen. Thefastener lumen may comprises a hole insert. The hole insert may comprisea proximal diameter, a middle diameter and a distal diameter, whereinthe proximal diameter is smaller than the middle diameter. Theorthopedic device may be an interbody spacer, a flanged interbodyspacer, a fixation plate, a vertebral fixation plate, or an anteriorcervical fixation plate.

In another embodiment, a method for securing an orthopedic device to abone is provided, comprising providing an orthopedic device comprising afastener lumen and a fastener, the fastener comprising a fastener headand a fastener body, the fastener head comprising a lumen opening, acentral internal lumen contiguous with the lumen opening, an internalscrew located within the central internal lumen, a side lumen contiguouswith the central internal lumen and an expansion member located at leastpartially within the side lumen and the central internal lumen andhaving an expanded configuration and a reduced configuration, attachingthe orthopedic device to a bone in a body, moving the internal screw toa position about the side lumen, partially displacing the expansionmember with respect to the side lumen, and changing the expansion memberto its expanded configuration. The fastener lumen may comprise a middlediameter and a proximal diameter, where the proximal diameter may beless than the middle diameter. The reduced configuration of theexpansion member may have a diameter less than the proximal diameter andthe expanded configuration of the expansion member may have a diameterbetween the proximal diameter and the middle diameter. Attaching theorthopedic device to a bone in a body may comprise inserting thefastener into the fastener lumen, and inserting the fastener into thebone of the body. The orthopedic device may be an interbody spacer. Theinterbody spacer may be a flanged interbody spacer, a fixation plate, avertebral fixation plate, or an anterior cervical fixation plate.

In another embodiment, a method for securing a device to an object isprovided, comprising providing a device comprising a fastener lumen anda fastener, the fastener comprising a fastener head and a fastener body,the fastener head comprising a lumen opening, a central internal lumencontiguous with the lumen opening, an internal screw located within thecentral internal lumen, a side lumen contiguous with the centralinternal lumen and an expansion member located at least partially withinthe side lumen and the central internal lumen and having an expandedconfiguration and a reduced configuration, attaching the device to anobject, moving the internal screw to a position about the side lumen,partially displacing the expansion member with respect to the sidelumen, and changing the expansion member to its expanded configuration.The fastener lumen may comprise a middle diameter and a proximaldiameter, where the proximal diameter may be less than the middlediameter. The reduced configuration of the expansion member may have adiameter less than the proximal diameter and the expanded configurationof the expansion member may have a diameter between the proximaldiameter and the middle diameter. Attaching the device to the object maycomprise inserting the fastener into the fastener lumen, and insertingthe fastener into the object.

In one embodiment, an intervertebral stabilization system is provided,comprising a first stabilization plate integrated with a first spacer,wherein the first stabilization plate may comprise an upper portion anda lower portion, and a second stabilization plate integrated with asecond spacer, wherein the second stabilization plate may comprise anupper portion and a lower portion, wherein the lower portion of thefirst stabilization plate may have a configuration complementary to theconfiguration of the upper portion of the second stabilization plate.The configuration of the lower portion of the second stabilization platemay be complementary to the configuration of the upper portion of thesecond stabilization plate, or may have a relative shape equal to therelative shape of the upper portion of the second stabilization platerotated 180 degrees. The upper portion of the first stabilization platemay comprise two attachment holes. The lower portion of the firststabilization plate may comprise one attachment hole. The intervertebralstabilization system may further comprise a third stabilization plateand a third spacer, wherein the configuration of the upper portion ofthe third stabilization plate may be complementary to the configurationof the lower portion of the second stabilization plate. The thirdstabilization plate may be integrated with the third spacer. The lowerportion of the third stabilization plate may have a configurationcomplementary to the configuration of the upper portion of the thirdstabilization plate, or may have a relative shape equal to the relativeshape of the upper portion of the third stabilization plate rotated 180degrees. The intervertebral stabilization system may further comprise afourth stabilization plate and a fourth spacer, wherein the upperportion of the fourth stabilization plate may have a configurationcomplementary to configuration of the lower portion of the thirdstabilization plate. The second stabilization plate and thirdstabilization plate have the same configuration. The lower portion ofthe second stabilization plate may have a relative shape equal to therelative shape of the upper portion of the second stabilization platerotated 180 degrees. The lower portion of the first stabilization platemay have a right-sided complementary shape and the upper portion of thesecond stabilization plate may have a left-sided complementary shape.The lower portion of the first stabilization plate may have a left-sidedcomplementary shape and the upper portion of the second stabilizationplate may have a right-sided complementary shape. The lower portion ofthe second stabilization plate may have a right-sided complementaryshape. The lower portion of the second stabilization plate may have aleft-sided complementary shape. The lower portion of the firststabilization plate may have an inside complementary shape and the upperportion of the second stabilization plate may have an outsidecomplementary shape. The lower portion of the first stabilization platemay have an underside complementary shape and the upper portion of thesecond stabilization plate may have a topside complementary shape.

In another embodiment, an orthopedic implant assembly is provided,comprising a stabilizing element having a trailing surface, a leadingsurface and at least one lumen, the lumen having a first opening at thetrailing surface, a second opening at the leading surface that may besmaller than the first opening, and a passageway extending from thefirst opening to the second opening, a securing element having anelongated body, a head at one end of the body and integral therewith,and a lumen insert member within a portion of the passageway, the lumeninsert member having an inner diameter and an outer diameter, andadapted to substantially reduce any force exerted between thestabilizing element and the securing element, wherein the diameter ofthe head of the securing element may be greater than the lesser diameterbetween the second opening of the lumen and the inner diameter of theinsert. The orthopedic implant assembly may further comprise aninterbody element integral with the leading surface of the stabilizingelement. The orthopedic implant assembly may further comprise a lockingassembly for resisting movement of securing element in at least onedirection.

In another embodiment, a method for treating a spine is provided,comprising providing an integrated stabilization plate and spacersystem, the integrated stabilization plate and spacer system comprisinga first integrated stabilization plate and first spacer and a secondintegrated stabilization plate and a second spacer, wherein eachstabilization plate has an upper portion and a lower portion and whereinthe lower portion of the first integrated stabilization plate has acomplementary shape to the upper portion of the second integratedstabilization plate, inserting the first spacer into a firstintervertebral space between a first vertebra and a second vertebra,attaching the upper portion of the first integrated stabilization plateto the first vertebra, attaching the lower portion of the firstintegrated stabilization plate to the second vertebra, inserting thesecond spacer into a second intervertebral space between the secondvertebra and a third vertebra, wherein the second intervertebral spaceis next to the first intervertebral space along a vertebral column,attaching the upper portion of the second integrated stabilization plateto the second vertebra, and attaching the lower portion of the secondintegrated stabilization plate to the third vertebra. Providing theintegrated stabilization plate and spacer system further may comprise athird integrated stabilization plate and a second spacer, wherein thelower portion of the second integrated stabilization plate may have acomplementary shape to the upper portion of the third integratedstabilization plate. The method for treating a spine may furthercomprise the steps of inserting the third spacer into a thirdintervertebral space between the third vertebra and a fourth vertebra,wherein the third intervertebral space is next to the secondintervertebral space along the vertebral column, attaching the upperportion of the third integrated stabilization plate to the thirdvertebra, and attaching the lower portion of the third integratedstabilization plate to the fourth vertebra.

In another embodiment, an implant for treating the spine is provided,comprising a stabilization plate comprising an access surface and a bonefacing surface, an upper portion and a lower portion, a spacer integralwith the stabilization plate at the bone facing surface, a firstattachment lumen between the access surface and the bone facing surfaceof the stabilization plate, the first attachment lumen having a firstattachment diameter adjacent to the access surface of the stabilizationplate, a lumen surface and a second attachment diameter adjacent to thebone facing surface of the stabilization plate, a retaining channelalong the lumen surface, and a third attachment diameter about theretaining channel, wherein the first attachment diameter may be greaterthan the second attachment diameter, a deformable retaining ring atleast partially located within the retaining channel, and a firstattachment lumen insert located at least partially in the firstattachment lumen and having an inner insert diameter and an outer insertdiameter. At least a portion of the spacer may comprise tissueengagement structures. The tissue engagement structures may compriseteeth. The implant for treating the spine may further comprise a bonescrew, the bone screw having a screw head and a screw body, wherein thescrew head has a head diameter less than the first attachment diameterand greater than the second attachment diameter. The implant fortreating the spine may further comprise a bone screw, the bone screwhaving a screw head and a screw body, wherein the screw head may have ahead diameter less than the first attachment diameter and greater thanthe inner insert diameter. The outer insert diameter may be greater thanthe second attachment diameter and the inner insert diameter may besmaller than the second attachment diameter. The second attachmentdiameter and the third attachment diameter may be generally equal. Thefirst attachment lumen insert may be located within the first attachmentlumen. The first attachment lumen insert may comprise an inner concavesurface. The screw head of the bone screw may comprise an outer convexsurface. The outer convex surface of the screw head may be complementaryto the inner concave surface of the first attachment lumen insert. Theimplant for treating the spine may further comprise a second attachmentlumen between the access surface and the bone facing surface of thestabilization plate, the lumen having a fourth attachment diameteradjacent to the access surface of the stabilization plate, a lumensurface and a fifth attachment diameter adjacent to the bone facingsurface of the stabilization plate.

In another embodiment, a method for treating a spine is provided,comprising providing a first stabilization plate integral with a firstspacer, wherein the first stabilization plate may comprise an upperportion, a lower portion and a plurality of attachment holes, wherein atleast one attachment hole comprises a retaining structure and anattachment insert, inserting the first spacer into a vertebral spacebetween a first vertebra and a second vertebra, attaching the upperportion of the first stabilization plate to the first vertebra, andattaching the lower portion of the first stabilization plate to thesecond vertebra. The at least one attachment hole further may comprise aretaining groove and the retaining structure may be a retaining ringpositioned in the retaining groove. The attachment insert may comprise aconcave surface. The retaining ring may be integral with the attachmentinsert. Attaching the upper portion of the first stabilization plate tothe first vertebra may comprise inserting a bone fastener through one ofthe plurality of attachment holes located in the upper portion of thefirst stabilization plate and engaging the first vertebra with the bonefastener. The method for treating a spine may further comprise providinga second stabilization plate integral with a second spacer, wherein thesecond stabilization plate may comprise an upper portion and a lowerportion. The lower portion of the first stabilization plate may have acomplementary configuration to the upper portion of the secondstabilization plate. The method for treating a spine may furthercomprise inserting the second spacer into a vertebral space between thesecond vertebra and a third vertebra.

In another embodiment, an implant for treating the spine is provided,comprising a fixation plate comprising an access surface and a bonefacing surface, an upper portion and a lower portion, a spacer connectedto the fixation plate at the bone facing surface, a first attachmentlumen between the access surface and the bone facing surface of thestabilization plate, the lumen having a first attachment diameteradjacent to the access surface of the stabilization plate, a lumensurface and a second attachment diameter adjacent to the bone facingsurface of the stabilization plate, a retaining channel along the lumensurface, and a third attachment diameter about the retaining channel,wherein the first attachment diameter is greater than the secondattachment diameter, a deformable retaining ring having a retainingsegment and a polyaxial segment and an abutting surface therebetween,wherein the retaining segment of the deformable retaining ring is atleast partially located within the retaining channel.

In another embodiment, an implant for treating the spine is provided,comprising a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion, a spacer, and anon-detachable articulation between the spacer and the bone facingsurface of the fixation plate. The non-detachable articulation may be ahinge joint. The hinge joint may have a joint axis that does notintersect the fixation plate. The hinge joint may have a joint axisconfigured to be generally perpendicular to a longitudinal axis of avertebral column when implanted. The hinge joint may have a joint axisconfigured to be generally parallel to a longitudinal axis of avertebral column when implanted. The non-detachable articulation may bea ball and socket joint. The non-detachable articulation may comprise ametal cord attached between the spacer and the bone facing surface ofthe fixation plate. The non-detachable articulation may be a pivotingarticulation.

In another embodiment, an implant for treating the spine is provided,comprising a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion, a spacer, and a pivotingarticulation between the spacer and the bone facing surface of thefixation plate. The pivoting articulation may be a hinge joint. Thehinge joint may have a joint axis configured to be generallyperpendicular to a longitudinal axis of a vertebral column whenimplanted. The hinge joint may have a joint axis configured to begenerally parallel to a longitudinal axis of a vertebral column whenimplanted. The pivoting articulation may be a ball and socket joint. Thepivoting articulation may comprise a metal cord attached between thespacer and the bone facing surface of the fixation plate. The pivotingarticulation may be a detachable articulation.

In another embodiment, an implant for treating the spine is provided,comprising a fixation plate having an access surface and a bone facingsurface, an upper portion and a lower portion, a spacer, and a rotatablearticulation between the spacer and the fixation plate and comprising anaxis of rotation, wherein the axis of rotation of the rotatablearticulation does not intersect the fixation plate. The axis of rotationof the rotatable articulation may be generally parallel to the fixationplate. The rotatable articulation may be configured to allow reversibleseparation of the fixation plate and spacer.

In one embodiment, an implant for treating the spine is provided,comprising a fixation plate comprising an access surface and a bonefacing surface, an upper portion, a lower portion, and at least oneattachment lumen between the access surface and the bone facing surface,a spacer connected to the bone facing surface of the fixation plate, anda locking plate configured to overlie the at least one attachment lumenand comprising an alignment structure to non-frictionally resistrotation of the locking plate when the locking plate may be partiallyattached to the fixation plate by a fastener. The fixation plate furthermay comprise two attachment lumens and the locking plate overlies atleast one of the two attachment lumens. The locking plate may overlieboth of the two attachment lumens. The fixation plate further maycomprise a third attachment lumen. The locking plate may overlie the twoattachment lumens and the third attachment lumen. The fixation platefurther may comprise a fourth attachment lumen. The locking plate mayoverlie the two attachment lumens, the third attachment lumen and thefourth attachment lumen. At least a portion of the spacer may comprisetissue engagement structures. The tissue engagement structures maycomprise teeth. The spacer may be integral with the bone facing surfaceof the fixation plate. The spacer may be connected to the bone facingsurface of the fixation plate by an articulation joint. The articulationjoint may be separable or non-separable. The lower portion of thefixation plate may have a configuration complementary to theconfiguration of the upper portion of the fixation plate. The alignmentstructure may comprise an elongate member and wherein the fixation platefurther may comprise an alignment lumen configured to accept theelongate member. The elongate member and the alignment lumen may beconfigured to resist rotation of the elongate member when in thealignment lumen. The locking plate may have an X-shaped configuration.The locking plate may have an H-shaped configuration. The locking platefurther may comprise a second alignment structure and wherein thefixation plate further may comprise a second alignment lumen configuredfor accepting the second alignment structure. The locking plate mayoverlie one of the two attachment lumens and the implant further maycomprise a second locking plate overlying the other of the twoattachment lumens.

In one embodiment, an implant for treating the spine is provided,comprising a flanged intervertebral spacer comprising a spacer body anda flange section, the flange section comprising an access surface and abone facing surface, an upper portion, a lower portion, four attachmentlumens between the access surface and the bone facing surface and twoalignment lumens, a locking plate comprising four attachment coversections and two alignment pins, wherein the four attachment coversections are configured to cover the four attachment lumens of theflange section and the two alignment pins are configured for insertioninto the two alignment lumens of the flange section.

In another embodiment, a system for attaching to a structure isprovided, comprising an attachment device having an access surface, afacing surface, a first attachment lumen between the access surface andthe facing surface of the attachment device, the first attachment lumenhaving a first attachment diameter adjacent to the access surface of theattachment device, a first lumen surface and a second attachmentdiameter adjacent to the facing surface of the attachment device, afirst retaining channel along the first lumen surface, and a thirdattachment diameter about the first retaining channel, wherein the firstattachment diameter may be greater than the second attachment diameter,and a side-biased blocking structure at least partially within theretaining channel having an uncompressed configuration that protrudesinto the first attachment lumen and a compressed configuration that doesnot protrude into the first attachment lumen. The blocking structure maycomprise a slope surface. The blocking structure may be an arcuatestructure. The arcuate structure may be a ring structure. The blockingstructure may be a rectangular plate with a through lumen. The throughlumen may be a circular through lumen. The attachment structure may bean interbody spacer. The interbody spacer may be a flanged interbodyspacer. The attachment structure may be a fixation plate. The attachmentstructure may be a vertebral fixation plate. The vertebral fixationplate may be an anterior cervical fixation plate. The blocking structuremay comprise a helical spring member. The blocking structure maycomprise a leaf spring member. The blocking structure may comprise anelongate bias member. The blocking structure may comprise a secondelongate bias member. The elongate bias member may have an arcuateshape.

In one embodiment, a method for treating the spine is provided,comprising providing an orthopedic device comprising a fastener lumen, asecuring structure space about the fastener lumen, a securing structurein the fastener lumen and the securing structure space, wherein thesecuring structure is a bias element and a non-deformable blockingelement, inserting a fastener into the fastener lumen, displacing atleast a portion of the non-deformable blocking element from the fastenerlumen into the securing structure space by compressing the bias element,and passing the head of the fastener past the non-deformable blockingelement to allow re-expansion of the bias element.

In another embodiment, a method for treating the spine is provided,comprising providing an orthopedic device comprising a fastener lumenwith a longitudinal lumen axis, a securing structure space about thefastener lumen, a securing structure in the fastener lumen and thesecuring structure space, wherein the securing structure may comprise abiased lumen blocker, inserting a fastener into the fastener lumen,eccentrically displacing the biased lumen blocker with respect to thelongitudinal axis of the fastener lumen, and passing the fastener pastbiased lumen blocker to allow reversion of the biased lumen blockertoward a prior position. The method for treating the spine may furthercomprise reverting the biased lumen blocker toward a prior position. Themethod for treating the spine may further comprise reverting the biasedlumen blocker to a prior position.

In one embodiment, a fastener is provided, comprising a fastener headand fastener shaft, the fastener head comprising a screw lumen, anexternal groove and one or more openings between the screw lumen andexternal groove, and an expandable member located at least partially inthe external groove and protruding through the one or more openings intothe screw lumen. The expandable member may be a ring. The fastener mayfurther comprise a secondary screw configured for the screw lumen.

In another embodiment, an orthopedic fastening system is provided,comprising a fastener comprising a fastener head and a threaded fastenerbody, wherein the fastener head may comprise a lumen opening, a centralinternal lumen contiguous with the lumen opening, a side lumencontiguous with the central internal lumen and an expansion memberlocated at least partially within the side lumen and having an expandedconfiguration and a reduced configuration. The fastener head further maycomprise an internal screw and located in the central internal lumen,the internal screw having a proximal position and a distal position. Theinternal screw in the proximal position may be located about the sidelumen and in the distal position may be located distal to the sidelumen. The proximal position of the internal screw may displace theexpansion member into the expanded configuration. The proximal positionof the internal screw may at least partially displace the expansionmember out of the side lumen. The proximal position of the internalscrew may allow the expansion member to be in the reduced configuration.The expansion member in the reduced configuration may be partiallylocated in the central internal lumen. The proximal position of theinternal screw at least partially displaces the expansion member out ofthe central internal lumen. The expansion member may be biased to thereduced configuration. The fastener head further may comprise anexpansion groove contiguous with the side lumen and the expansion membermay comprise an elongate body positioned about the expansion groove. Theelongate body may be an arcuate elongate body. The expansion memberfurther may comprise a radial elongate body located at least partiallyin the side lumen. The orthopedic fastening system may further comprisean orthopedic device comprising a fastener lumen adapted to retain thefastener. The fastener lumen may comprise a proximal diameter, a middlediameter and a distal diameter, wherein the proximal diameter may besmaller than the middle diameter. The distal diameter of the fastenerlumen may be smaller than the proximal diameter of the fastener lumen.The fastener lumen may comprise a hole insert. The hole insert maycomprise a proximal diameter, a middle diameter and a distal diameter,wherein the proximal diameter may be smaller than the middle diameter.The orthopedic device may be an interbody spacer. The interbody spacermay be a flanged interbody spacer. The orthopedic device may be afixation plate. The orthopedic device may be a vertebral fixation plate.The vertebral fixation plate may be an anterior cervical fixation plate.

In another embodiment, a method for securing an orthopedic device to abone is provided, comprising providing an orthopedic device comprising afastener lumen and a fastener, the fastener comprising a fastener headand a fastener body, the fastener head comprising a lumen opening, acentral internal lumen contiguous with the lumen opening, an internalscrew located within the central internal lumen, a side lumen contiguouswith the central internal lumen and an expansion member located at leastpartially within the side lumen and the central internal lumen andhaving an expanded configuration and a reduced configuration, attachingthe orthopedic device to a bone in a body, moving the internal screw toa position about the side lumen, partially displacing the expansionmember with respect to the side lumen, and changing the expansion memberto its expanded configuration. The fastener lumen may comprise a middlediameter and a proximal diameter, where the proximal diameter may beless than the middle diameter. The reduced configuration of theexpansion member may have a diameter less than the proximal diameter andthe expanded configuration of the expansion member may have a diameterbetween the proximal diameter and the middle diameter. Attaching theorthopedic device to a bone in a body may comprise inserting thefastener into the fastener lumen, and inserting the fastener into thebone of the body. The orthopedic device may be an interbody spacer. Theinterbody spacer may be a flanged interbody spacer. The orthopedicdevice may be a fixation plate. The orthopedic device may be a vertebralfixation plate. The vertebral fixation plate may be an anterior cervicalfixation plate.

In another embodiment, a method for securing an device to an object isprovided, comprising providing a device comprising a fastener lumen anda fastener, the fastener comprising a fastener head and a fastener body,the fastener head comprising a lumen opening, a central internal lumencontiguous with the lumen opening, an internal screw located within thecentral internal lumen, a side lumen contiguous with the centralinternal lumen and an expansion member located at least partially withinthe side lumen and the central internal lumen and having an expandedconfiguration and a reduced configuration, attaching the device to anobject, moving the internal screw to a position about the side lumen,partially displacing the expansion member with respect to the sidelumen, and changing the expansion member to its expanded configuration.The fastener lumen may comprise a middle diameter and a proximaldiameter, where the proximal diameter may be less than the middlediameter. The reduced configuration of the expansion member may have adiameter less than the proximal diameter and the expanded configurationof the expansion member may have a diameter between the proximaldiameter and the middle diameter. Attaching the device to the object maycomprise inserting the fastener into the fastener lumen, and insertingthe fastener into the object.

The above embodiments and methods of use are explained in more detailbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and method of using the invention will be betterunderstood with the following detailed description of embodiments of theinvention, along with the accompanying illustrations, in which:

FIG. 1 is a lateral elevational view of a portion of the vertebralcolumn.

FIGS. 2A and 2B are superior and lateral elevational views of a thoracicvertebra.

FIG. 3 illustrates a superior elevational view of a cervical vertebra.

FIG. 4 represents a superior elevational view of a lumbar vertebra.

FIGS. 5A through 5C are perspective, superior and lateral elevationalviews of one embodiment of an integrated fixation plate and spacer.

FIG. 6 is a superior elevational view of another embodiment of anintegrated fixation plate and spacer.

FIG. 7 is a superior elevational view of another embodiment of anintegrated fixation plate and spacer.

FIGS. 8A and 8B illustrate superior and lateral elevational views ofanother embodiment of an integrated fixation plate and spacer.

FIGS. 9A and 9B illustrate superior and lateral elevational views ofanother embodiment of an integrated fixation plate and spacer.

FIGS. 10A and 10B are schematic perspective and lateral views of oneembodiment of the invention attached to a vertebral column. FIGS. 10Cand 10D are schematic perspective and lateral views of anotherembodiment of the invention attached to a vertebral column with angledscrews.

FIG. 11 depicts a cross sectional magnified view of one embodiment of ascrew and a fixation plate hole.

FIG. 12 depicts a cross sectional magnified view of one embodiment of ascrew and a polyaxial fixation plate hole.

FIG. 13A is a perspective view of one embodiment of the inventioncomprising a retaining ring and fixation hole insert. FIGS. 13B and 13Care cross sectional views of the device in FIG. 13A.

FIG. 14 is a cross sectional view of another embodiment of the inventioncomprising an angled retaining ring.

FIGS. 15A and 15B are frontal and perspective views of one embodiment ofa complementary two spacer system.

FIGS. 16A and 16B are frontal and perspective views of one embodiment ofa complementary three spacer system.

FIGS. 17A and 17B are frontal and perspective views of one embodiment ofa complementary four spacer system.

FIG. 18 is a frontal view of one embodiment of the invention comprisinga variable width spacer system.

FIG. 19 is a frontal view of one embodiment of the invention comprisinga variable height spacer system.

FIG. 20 is a frontal view of one embodiment of a complementary identicalfour spacer system.

FIG. 21 is a frontal view of another embodiment of a complementary threespacer system.

FIG. 22 is a frontal view of another embodiment of a complementary fourspacer system.

FIG. 23 is a frontal view of one embodiment of a complementary fivespacer system.

FIG. 24 is a frontal view of another embodiment of a complementary fourspacer system.

FIGS. 25A and 25B represent frontal and lateral views of one embodimentcomprising a complementary overlapping spacer system.

FIGS. 26A to 26D are various views of a pivotable interbody-platedevice.

FIG. 27 is isometric elevational view of another embodiment of afastener retaining assembly.

FIG. 28 is a cross-sectional view of a fixation device with the fastenerretaining assembly of FIG. 27 and an inserted screw.

FIG. 29A is a cross-sectional view of another embodiment of a fastenerwith an expansion ring. FIG. 29B is an exploded view of the fastener andexpansion ring in FIG. 29A.

FIGS. 30A and 30B are superior oblique views of a fastener retainingbody with side-bias members in uncompressed and compressed positions,respectively.

FIG. 31 is an oblique cut-away view of the fastener retaining body inFIG. 30A within a retaining body space about a fastener lumen.

FIG. 32A is a superior elevational of a fastener head positioned withina fastener lumen whereby the fastener has displaced the fastenerretaining body into the compressed position. FIGS. 32B and 32C aresuperior side cross-sectional views of fastener head and fastenerretaining body from FIG. 32A.

FIG. 33A is a superior elevational of a fastener head positioned withina fastener lumen whereby the fastener head has fully passed through thefastener retaining body and the fastener retaining body has reverted toits uncompressed configuration. FIGS. 33B and 33C are superior sidecross-sectional views of fastener head and fastener retaining body fromFIG. 33A.

FIG. 34A is an anterior elevational view of one embodiment of theinvention comprising a locking plate and flanged interbody fusiondevice. FIG. 34B depicts the locking plate of FIG. 34A separated fromthe flanged interbody fusion device.

FIGS. 35A and 35B are oblique and anterior elevational views of anotherembodiment of the invention comprising dual locking plates.

FIGS. 36A and 36B are side and anterior elevational view of anotherembodiment of the invention comprising an angled locking plate.

FIG. 37 is a cross-sectional view of another embodiment of a fastenerwith an expansion ring.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Advancing age, as well as injury, can lead to degeneration in the bones,discs, joints, and ligaments of the spine producing pain from nerve rootcompression. Under certain circumstances, alleviation of pain can beprovided by performing a spinal fusion. Spinal fusion is a procedurethat involves joining two or more adjacent vertebrae so that they nolonger are able to move relative to each other.

In existing spinal fusion implants there have also been problems withloosening and backing out of screws into the patient's throat area.Backout is the exhibited tendency of bone screws, which affix the boneplate to the bone(s), to loosen with respect to both the plate and bone,resulting in poor fixation, fusion and ultimately, healing. Essentially,this loosening of the bone screw causes the screw to work itself out ofthe bone into which it is implanted. This results in the bone platebeing poorly fixed in place thus becoming devoid of its fixationcapabilities. Usually, backout is caused by the chronic stress of bodilymovement. While such loosening can be benign if limited in scope, it maylead to complications such as complete failure of the fixation device orincomplete bone fusion. Backout is particularly prevalent in areas ofhigh bodily stress and movement, such as the spine.

To alleviate backout and its associated problems, current systemsutilize secondary locking screws, locking collars or other secondarylocking devices that hold the bone screws in place after deploymentwithin the bone. In most systems, the bone screw is affixed into thebone through an opening in a bone plate. A locking device is theninserted into the bone screw. The locking device engages the head of thebone screw and is tightened which results in the bone screw being fixedin place within the bone, thus preventing backout.

While a locking screw or collar can alleviate backout, successful use ofsuch locking device systems in the anterior cervical spine isparticularly difficult because of anatomic constraints. Systems usingmultiple types of screws or collars to hold the bone screw in place aredifficult to deploy within the confines of a small operating areaavailable at the cervical spine. Furthermore, due to the small operatingarea, the surgeon implanting the device has great difficulty determiningif the device is properly deployed. Any instrumentation implanted in theregion must be minimally intrusive, yet have adequate strength towithstand the biomechanical loads to which it will be subjected. Thus,while current systems can help reduce instances of backout, theircomplex nature makes proper deployment very difficult and increases thechance of surgical error.

There is a need for an implant having a locking mechanism that can beeasily and reliably locked in place to prevent the loosening of andbacking out of the bone screws used to attach the implant to thevertebrae in the anterior aspect of the cervical, thoracic, and lumbarspine.

There is also a need for implants that can be implanted along a seriesof adjacent vertebrae. Implants adapted for use in the lumbar spine andthe thoracic spine become much less usable in the cervical spine becauseof differences in anatomy. In the lumbar spine, the disc spaces areabout 25% as tall as the vertebral bodies (i.e., the vertebral bodiesare generally four times taller than the intervening disc space). In thecervical spine, the disc space can be 50% of the height of the vertebralbodies. The disc spaces in the cervical spine are generally not greaterthan 7 or 8 mm tall in most people.

Attachment of one fixation plate between two vertebrae often preventsthe attachment of additional fixation plates between one of twovertebrae and an adjacent vertebra. This is especially true in thecervical spine region. The attachment of one fixation plate will reducethe surface area available to attach another fixation plate due to thesmall size of the cervical vertebrae and the minimum size required foreach fixation plate. Because of this limitation in existing spinalfixation devices, treatment of spinal disorders may be suboptimalbecause disease in adjacent vertebrae cannot be treated adequately.

A. ANATOMY OF THE SPINE

As shown in FIG. 1, the vertebral column 2 comprises a series ofalternating vertebrae 4 and fibrous discs 6 that provide axial supportand movement to the upper portions of the body. The vertebral column 2typically comprises thirty-three vertebrae 4, with seven cervical(C1-C7), twelve thoracic (T1-T12), five lumbar (L1-15), five fusedsacral (S1-S5) and four fused coccygeal vertebrae. FIGS. 2A and 2Bdepict a typical thoracic vertebra. Each vertebra includes an anteriorbody 8 with a posterior arch 10. The posterior arch 10 comprises twopedicles 12 and two laminae 14 that join posteriorly to form a spinousprocess 16. Projecting from each side of the posterior arch 10 is atransverse 18, superior 20 and inferior articular process 22. The facets24, 26 of the superior 20 and inferior articular processes 22 form facetjoints 28 with the articular processes of the adjacent vertebrae.

The typical cervical vertebrae 30, shown in FIG. 3, differ from theother vertebrae with relatively larger spinal canals 32, oval shapedvertebral bodies 34, bifid spinous processes 36 and foramina 38 in theirtransverse processes 40. These foramina transversaria 38 contain thevertebral artery and vein. The first and second cervical vertebrae alsofurther differentiated from the other vertebrae. The first cervicalvertebra lacks a vertebral body and instead contains an anteriortubercle. Its superior articular facets articulate with the occipitalcondyles of the skull and are oriented in a roughly parasagittal plane.The cranium is able to slide forward and backwards on this vertebra. Thesecond cervical vertebra contains an odontoid process, or dens, whichprojects superiorly from its body. It articulates with the anteriortubercle of the atlas, forming a pivot joint. Side to side movements ofthe head occur at this joint. The seventh cervical vertebra is sometimesconsidered atypical since it lacks a bifid spinous process.

Referring to FIG. 4, the typical lumbar vertebrae 42 is distinguishablefrom the other vertebrae by the absence of foramina transversaria andthe absence of facets on the surface of the vertebral body 44. Thelumbar vertebral bodies 44 are larger than the thoracic vertebral bodiesand have thicker pedicles 46 and laminae 48 projecting posteriorly. Thevertebral foramen 50 is triangular in shape and larger than the foraminain the thoracic spine but smaller than the foramina in the cervicalspine. The superior 52 and inferior articular processes (not shown)project superiorly and inferiorly from the pedicles, respectively.

B. FLANGED SPACER

In one embodiment of the invention, an interbody vertebral implant 100is provided. As shown in FIGS. 5A through 5C, in one embodiment, theimplant 100 comprises a stabilization or fixation plate 102 having anupper portion 104 and a lower portion 106, and a bone facing surface 108and an access surface 110. In use, typically the bone facing surface 108will actually contact the vertebral bone surface, but in otherembodiments, other structures or components may lie in between the bonefacing surface 108 and the bone surface of the vertebra. Each upperportion 104 and lower portion 106 has one or more spaces or holes 112oriented between the bone facing surface 108 and the access surface 110that are configured to accept screws and/or other attachment devices foranchoring the implant 100 to the vertebral bone. One or more spacers orspacing structures 114 are located on the bone facing surface 108 of thefixation plate 102. The spacers 114 are typically integrated with thefixation plate 102 about the bone facing surface 108.

1. Spacer Component

The spacer may comprise any structure configured to maintain aseparation and resist compression between two adjacent vertebral bodies.The spacer may have any of a variety of overall shapes, including butnot limited to a rectangular box, a trapezoidal box, H-shaped, O-shaped,V-shaped, with or without one or more lumens within the spacingstructure. As shown in FIGS. 5B and 5C, the spacer 114 has a base 116, asuperior surface 118 and an inferior surface 120, and side surfaces 122,124, and a posterior surface 126. Each surface 118, 120, 122, 124, 126need not be flat, and may be curved or undulating or any combinationthereof. The upper and lower surfaces 118, 120 are configured for facingthe superior and inferior vertebral bodies 8 or 34 adjacent to animplantation site. The relative configuration of the upper surface 118and lower surface 120 may vary, depending upon the relative positiondesired between the two adjacent vertebrae, the anatomical shape of thevertebrae, ease of insertion of the implant and other factors. Forexample, if a neutral vertical alignment is desired between twovertebrae, the upper and lower surfaces 118, 120 may have generallyparallel planar orientations. If a non-neutral alignment is desired, forinstance to maintain a natural spinal curvature in the cervical region,the upper and lower surfaces 118, 120 may have a wedge-like relationshipto allow fixation of the vertebrae in the desired non-neutral position.A non-neutral alignment with respect to the anterior-posterior directionmay also be used to compensate for excessive lordosis or kyphosis inother portions of the vertebral column. The height of the spacingstructure 116 at any section between the upper and lower surfaces 118,120 may be further configured to accommodate degenerative changes oranatomical anomalies to provide fixation in the desired relativeposition. Likewise, the side surfaces 122, 124 of the spacing structure114 may be generally parallel or skewed. In one embodiment, the sidesurfaces 122, 124 of the implant 100 taper with increasing distance fromthe base 116 of the implant 100. A tapered spacing structure mayfacilitate insertion of the implant 100 into the intervertebral space.In other embodiments, the one or more side surfaces may flare distallyor have both tapering and flaring portions.

The device depicted in FIGS. 5B and 5C is one embodiment of theinvention comprising a closed-shaped spacer 114 with a lumen 128 betweenthe superior and inferior surfaces 118, 120. The side surfaces 122, 124may have a slight taper along the posterior direction. FIG. 6 depictsone embodiment of the invention with a block spacer 130 that lacks aspacer lumen. FIG. 7 depicts another embodiment comprising an H-shapedspacer 132 with two protruding members 134, 136 and one bridge member138 between the two protruding members 134, 136. The bridge member 138may be oriented in any of a variety of positions between the twoprotruding members 134, 136. The two protruding members 134, 136 neednot have a similar or symmetrical shape. Some embodiments of theinvention may have more than two protruding members 134, 136 and/or oneor more bridge members 138.

FIGS. 8A and 8B illustrate another embodiment of the inventioncomprising a spacer 140 with two posterior members 142, 144 where eachposterior member 142, 144 has a window or hole 146 between the outerside surface 148 and inner side surface 150 of the posterior member.This window or hole may allow bony growth into the window or hole andbetween the two posterior members 142, 144. The space 146, 152 withinand/or between the posterior members 142, 144 may also be filled withgraft materials (not shown). The graft material may be an autograft,allograft, xenograft or synthetic material. Synthetic graft material maybe ceramic-based, silicon-based or calcium-based. The graft material mayalso include osteoinductive factors to promote bone ingrowth. Oneskilled in the art will appreciate that there are many varieties ofsynthetic graft materials and constituents that may be used between orabout the hyoid bone segments.

One or more surfaces of the implant may also have surface projections,indentations, or holes or pores that can further alter thecharacteristics of the implant. Referring to FIGS. 9A and 9B, in oneembodiment, angled projections, barbs, teeth 154 or ramped surfaceswhich incline outwardly from one or more spacer surfaces toward thefixation plate 102 may be provided on one or more surfaces that allowinsertion of the spacing structure in one direction but resist movementin the opposite direction. These teeth 154 may be advantageous inreducing the migration of the device out of the intervertebral space.Improved fixation of the spacer 156 may maintain device position duringdrilling of the screw holes into the vertebral bodies, and may alsoreduce the forces acting upon the screws or other retaining structures,thereby reducing the risk of backout. The teeth 154 are preferablyprovided on the superior and/or inferior surfaces 118, 120 of the spacer156, but other surfaces may also have teeth or other tissue engagementstructures.

As illustrated in FIGS. 9A and 9B, in one embodiment, the tissueengagement structures may be combined with indentations, holes or poresfor allowing bony ingrowth or filling with bony matrix or graftmaterials as previously described. These holes may be utilized withother surface features to further enhance insertion and stabilization ofthe implant.

In one embodiment, the spacer has a height of about 4 mm to about 50 mm,or preferably about 4 mm to about 12 mm. Occasionally, the spacer has aheight of about 6 mm to about 9 mm. In some embodiments, the spacer hasa length along the AP axis, as measured from the bone facing surface ofthe fixation plate to the most posterior end of the spacer, of about 5mm to about 25 mm. In some embodiments, the spacer length is about 10 mmto about 15 mm. The width of the spacer is generally about 5 mm to about25 mm, and in some situations, about 10 mm to about 15 mm. One skilledin the art can dimension the spacer based upon the implantation locationand specific vertebral morphology, neurological anatomy and diseasestate.

The spinal fusion implant may include, be made of, treated, coated,filled, used in combination with, or contain artificial or naturallyoccurring materials suitable for implantation in the human spine. Thesematerials include any source of osteogenesis, bone growth-promotingmaterials, bone derived substances, bone morphogenetic proteins,hydroxyapatite, genes coding for the production of bone, and boneincluding, but not limited to, cortical bone. The implant can also beformed of material such as metal including, but not limited to, titaniumand its alloys, surgical grade plastics, plastic composites, ceramics,or other materials suitable for use as a spinal fusion implant. In someembodiments, the device comprises a radiolucent material, a radio-opaquematerial, or a combination thereof. A device that is partially orcompletely radiolucent may be advantageous when evaluating the effect ofthe implant post-implantation. Many existing spinal fixation platesand/or spacers obscure visualization of the vertebrae, which cancomplicate post-operative treatment, diagnosis and prognosis of thepatient's condition. The implant may include at least in part materialsthat are bioabsorbable in the body. The implant of the present inventioncan be formed of a porous material or can be formed of a material thatintrinsically participates in the growth of bone from one of adjacentvertebral bodies to the other of adjacent vertebral bodies. The implantmay be treated with, coated with, or used in combination with substancesto inhibit scar tissue formation. The implant of the present inventionmay be modified, or used in combination with materials to provideantibacterial properties, such as, but not limited to, electroplating orplasma spraying with silver ions or other substance. The implant mayoptionally comprise an electrical source to provide ionophoresis of thesilver ions into the surrounding tissue to prevent infection. Theantibacterial properties may include bactericidal and/or bacteriostaticcharacteristics. Similarly, anti-fungal characteristics may also beprovided. Any of these materials as appropriate may be used at any timeafter the implant(s) are inserted.

2. Fixation Component

The fixation plate may have a generally flat configuration, curvedconfiguration or combination thereof. Optionally, each surface of thefixation plate may also have a generally flat or curved configuration orcombination thereof. Each surface of the fixation plate need not havethe same configuration. The edges of the fixation plate may optionallybe rounded, smoothed or polished. In one embodiment, the flange isdimensioned such that flange extends about 2 mm beyond the edges of thebase of the spacer. In some embodiments of the invention, the fixationcomponent is dimensioned to extend generally about 1 mm to about 20 mmbeyond the cross sectional border of the spacer component at itsinterface with the fixation plate. In other embodiments, the flange mayextend by 3 mm or 4 mm or more beyond the spacer base. The flange may ormay not extend uniformly along the spacer edges. The shape of the flangemay be different from the shape of the spacer base.

In some embodiments, the average thickness of the fixation plate iswithin the range of about 1 mm to about 5 mm. In other embodiments, theaverage thickness of the fixation plate is within the range of about 1.5mm to about 3.0 mm. The thicknesses of the fixation plate need not to beuniform. In one embodiment, the fixation plate is conformable to thevertebral surfaces of the implantation sites.

In other embodiments of the invention, the spacer component is attachedto a fixation component comprising a mesh or lattice. The fixationcomponent may also be made from a material that is the same or differentfrom the spacer component. In some instances a fixation component and aspacer component having different materials may be beneficial becausethe spacer component may be configured to withstand compressive forceswhile the fixation component is configured to withstand primarilytension forces. The fixation component may comprise a polymer, a wovenmaterial, or a combination thereof.

Referring back to FIGS. 5A through 5C, each upper portion and lowerportion of the fixation plate 102 has one or more spaces or holes 112oriented between the bone facing surface 108 and access surface 110 thatare configured to accept screws and/or other attachment elements foranchoring the implant to the vertebral bone. As shown in FIGS. 10A and10B, in some embodiments of the invention, one or more bone screws 158configured for insertion through one or more screw holes 112 in thefixation plate 102 are provided. As shown in FIGS. 10C and 10D, eachbone screw 158 typically comprises a screw head 160 and a screw body162. The bone screws 158 and/or anchors may or may not be self-tapping.In some embodiments, the invention further comprises bone anchorscomprising an anchor head and an anchor body. The anchor head is adaptedto interface with the fixation plate to hold the fixation plate againstthe adjacent vertebral bone structures. The anchor body comprisesthreads or barbs for piercing or inserting into bone and fixing theposition of the anchor head. The anchor body may or may not form aninterface with the holes of the fixation plate to further fix theposition of the fixation plate with respect to the vertebral bone.

Each hole 112 of the flange or fixation plate 102 need not have the sameconfiguration or size. The holes 112 are typically round in crosssection and dimensioned to allow passage of a screw body 162therethrough while resisting passage of the screw head 160 completelythrough the hole 112. In other embodiments, however, at least a portionof the hole 112 may have a non-round cross-section, such as an oval,square, rectangle, polygonal or other closed shape. The inside surfaceof the holes 112 may be covered with a lubricious coating to facilitateinsertion and/or movement of a screw or other attachment device throughthe hole.

In one embodiment, depicted in each hole FIG. 11, comprises a firstinside surface 164 adjacent to the access surface 110 having a firstdiameter 166, and a second inside surface 168 adjacent to the bonefacing surface 108 having a second diameter 170. In some embodiments,either one or both of the first inside surface 164 and second insidesurface 168 may be dimensioned to align a corresponding screw 172 ingenerally one particular orientation. In one embodiment, the secondinside surface 168 of a screw hole 112 comprises threads 174 and adaptedto form a rotatable mechanical interfit with threads 176 on acorresponding screw 172 inserted through the hole 112. The first insidesurface 164 of the screw hole 112 may also be similarly threaded, or maybe configured to accept the head 178 of a screw 172 inserted through thehole 112 to allow flush positioning or recessed positioning of the screwhead 178 with the access surface 110 of the fixation plate 102.

The bone anchor or screw 172 for the particular flange hole 112 istypically selected so that the largest diameter of the screw or anchorhead 178 is larger than the second diameter 170 of the hole 112. Fornon-recessed screws or anchors, the largest diameter of the screw oranchor head 178 may be larger than the first diameter 166. For flush,partially or completely recessed screws or anchors, the largest diameterof the screw or anchor head 178 is between the first diameter 166 andthe second diameter 170. In one embodiment, the flange holes 112 mayhave a first diameter 166 of about 3 mm to about 10 mm, and in otherembodiments, may have a diameter of about 4 mm to about 6 mm. In oneembodiment, the flange holes 112 may have a second diameter 170 of about0.1 mm to about 4.0 mm smaller than the first diameter, and in oneembodiment, may have a second diameter 170 of about 0.2 mm to about 1.0mm smaller than the first diameter 166, or even about 0.2 mm to about0.4 mm smaller than the first diameter 166. In one embodiment, the screwhead or anchor head 178 may have a diameter of about 3.2 mm to about10.2 mm, and in one embodiment, may have a diameter of about 4.4 mm toabout 6.4 mm.

For embodiments where the first inside surface 164 of the hole 112 isadapted for recessed positioning of the screw head 178, the recessedpositioning may be partial or complete. With partial recessedpositioning, only a portion of an inserted screw lies below the accesssurface 112 of the fixation plate 102, while with complete recessedpositioning, all the screw head 178 may lie at or below the accesssurface 112 of the fixation plate 102. The screw hole 112 about thefirst inside surface 164 can have any of a variety of cross sectionalshapes.

In some embodiments, the one or more holes are configured to align ascrew 172 having a general perpendicular orientation with respect toeither or both the access surface 110 or bone facing surface 108 of theflange 102. In some embodiments, one or more holes 112 may be configuredto align a screw in a skewed orientation. Sometimes, the skewedorientation may have a slight superior or inferior angle, depending uponwhether the hole is located on the upper portion or lower portion of theflange, respectively. A skewed orientation in the superior/inferiordirection may reduce the risk that the screw 172 remains secure in thevertebral body by providing sufficient bone structure between the screwbody and the intervertebral space. In one embodiment, a screw hole 112is configured to accept a screw 172 in an orientation that is within therange of about 0 degrees to about 60 degrees superiorly with respect tothe plane between the two corresponding vertebrae. In one embodiment,the screw hole is configured to accept a screw 172 in an orientationthat is within the range of about 5 degrees to about 30 degreessuperiorly, and in some embodiments, to accept a screw 172 in anorientation that is within the range of about 10 degrees to about 20degrees superiorly. In one embodiment, a screw hole 172 is configured toaccept a screw 172 in an orientation that is within the range of about 0degrees to about 60 degrees inferiorly with respect to the transverseplane between the two corresponding vertebrae 4. In one embodiment, thescrew hole 112 is configured to accept a screw 172 in an orientationthat is within the range of about 5 degrees to about 30 degreesinferiorly, and in some embodiments, to accept a screw 172 in anorientation that is within the range of about 10 degrees to about 20degrees inferiorly. The particular orientation of a screw hole 112 maybe determined by the dimensions of the screw 172 used with the deviceand the vertebrae 4 to which the device is to be attached.

One or more holes 112 of the flange 102 may also be configured to askewed angle in the medial/lateral direction. Typically, the hole 112may be configured with a medially directed screw orientation to avoidinsertion of a screw through the outer surface of the vertebral body orthrough a pedicle, but a lateral screw orientation may also be used.Screw holes 112 located medially on the flange 102 may have a lateralorientation. In one embodiment, a screw hole 112 is configured to accepta screw 172 in an orientation that is within the range of about 0degrees to about 45 degrees medially with respect to the sagittal planethrough a vertebra 4. In one embodiment, the screw hole 112 isconfigured to accept a screw 172 in an orientation that is within therange of about 5 degrees to about 30 degrees medially, and in someembodiments, to accept a screw 172 in an orientation that is within therange of about 10 degrees to about 20 degrees medially. In oneembodiment, a screw hole 112 is configured to accept a screw 172 in anorientation that is within the range of about 0 degrees to about 45degrees lateral with respect to the sagittal plane through the vertebrae4. In one embodiment, the screw hole is configured to accept a screw 172in an orientation that is within the range of about 5 degrees to about30 degrees laterally, and in some embodiments, to accept a screw 172 inan orientation that is within the range of about 10 degrees to about 20degrees laterally. One or both of the first and second inside surfaces165, 168 may be threaded and capable of forming a rotatable interfitwith the threads of a corresponding screw 172 or other attachmentdevice. One or more holes 112 of the flange 102 may also be configuredto accept and/or orient the tip of a corresponding drill guide so thatscrew holes in the vertebrae 4 may be created after the device has beenpositioned at its implantation site. By drilling screw holes into thevertebrae 4 after the positioning of the device, the risk of misalignedvertebral screw holes and flange holes 112 may be reduced. Misalignmentmay result in an ill-fitting and unstable implant.

In some embodiments of the invention, shown in FIG. 12, one or morescrew holes of the fixation plate or flange may be configured to allow arange of corresponding screw orientations when the screw is insertedthrough the screw hole. In one embodiment of the invention, a polyaxialscrew hole 180 wherein at least a portion of the inner surface 182 ofthe polyaxial screw hole 180 having a concave surface 184 that iscapable of accepting a range of screw orientations within the screw hole180. The concave surface 184 typically comprises an entire circumferenceof the inner surface of the screw hole 180, but in some embodiments, maycomprise only one or more portions of a screw hole 180 circumference.Concave surfaces along limited portions of a circumference may allowpivoting or a range of movement along one axis of the screw hole 180while limiting the pivoting along another axis of the screw hole 180. Insome embodiments, the distal surface 188 of the screw head 190 may beconfigured with a convexity complimentary to the concave surface 184 ofthe screw hole 180.

In one embodiment, a screw hole 180 is configured to provide a screworientation range of about 0 degrees to about 60 degrees from thecentral axis of the screw hole. In one embodiment, the screw hole 180 isconfigured to provide a screw orientation range up to about 5 degrees toabout 30 degrees from the central axis of the screw hole, and in someembodiments, to provide a screw orientation range up to about 10 degreesto about 20 degrees. In one embodiment, a screw hole 180 is configuredto provide a screw orientation range of about 0 degrees to about 60degrees superiorly with respect to the plane between the twocorresponding vertebrae 4. In one embodiment, the screw hole 180 isconfigured to provide a screw orientation range of about 5 degrees toabout 30 degrees superiorly, and in some embodiments, to provide a screworientation range of about 10 degrees to about 20 degrees superiorly. Inone embodiment, a screw hole 180 is configured to provide a screworientation range of about 0 degrees to about 60 degrees inferiorly withrespect to the transverse plane between the two corresponding vertebrae.In one embodiment, the screw hole 180 is configured to provide a screworientation range of about 5 degrees to about 30 degrees inferiorly, andin some embodiments, to provide a screw orientation range of about 10degrees to about 20 degrees inferiorly. The particular orientation of ascrew hole may be determined by the dimensions of the screw 186 usedwith the device and the vertebrae 4 for which the device is to beattached. One or more holes 180 of the flange 102 may also be configuredto a skewed angle in the medial/lateral orientation. Typically, the hole180 may be configured with a medially directed screw orientation toavoid insertion of a screw 186 through the outer surface of thevertebral body 8 or through a pedicle 12, but a lateral screworientation may also be used. In one embodiment, a screw hole isconfigured to provide a screw orientation range of about 0 degrees toabout 45 degrees medially with respect to the sagittal plane through avertebra. In one embodiment, the screw hole is configured to provide ascrew orientation range of about 5 degrees to about 30 degrees medially,and in some embodiments, to provide a screw orientation range of about10 degrees to about 20 degrees medially. In one embodiment, a screw holeis configured to provide a screw orientation range of about 0 degrees toabout 45 degrees lateral with respect to the sagittal plane through thevertebra. In one embodiment, the screw hole is configured to provide ascrew orientation range of about 5 degrees to about 30 degreeslaterally, and in some embodiments, to provide a screw orientation rangeof about 10 degrees to about 20 degrees laterally. FIGS. 10A and 10Bdepict one embodiment of the invention comprising an implant with asquare-shaped flange 102 with four polyaxial screw holes 164 wherein thescrews used to secure the implant to the vertebrae were inserted with anorientation that is in a generally neutral orientation with respect tothe bone facing surface 108 of the flange or fixation plate 102. In oneembodiment, the screw holes 164 in the upper portion of the flange 102may be configured in the vertical axis to allow an insertion angle ofabout +30 degrees to about −15 degrees. The screw holes 164 in the lowerportion of the flange 102 may be configured to provide an insertionrange of about +20 degrees to about −5 degrees in the vertical axis.FIGS. 10C and 10D shows the use of the implant in FIGS. 10A and 10B withat least one screw 158 inserted through an upper screw hole 164 of theimplant and into the upper vertebral body of an intervertebral spacewith a superiorly angled orientation. In some instances, this screworientation may reduce the risk of bone fracture into the intervertebralspace with or without migration of the screw body into the same space.

In one embodiment of the invention, one or more additional screw holestructures are provided to further interact with an inserted screw.FIGS. 13A through 13C depict one embodiment of the invention comprisingan expandable/collapsible retainer ring or collar 200. The retainerring/collar 200 allows insertion of a corresponding screw 202 in onedirection through a screw hole 204 but resists movement of the screw 202in the opposite direction. The retainer ring/collar 200 may bepositioned within one or more screw holes 204 with a recess orindentation 206 along at least a portion of its circumference capable ofaccepting at least the outside diameter portion of the retainerring/collar 200. The recess or indentation 206 typically comprises acircumferential channel of the flange hole 204 having a recess diameter208 that greater than the first diameter 210 of the flange hole 204. Therecess or indentation 208 is typically located closer to the accesssurface 110 of the fixation plate 102, rather than the bone facingsurface 108, but may also be located at other positions within the screwhole 204. The ring or collar 200 has an outside retainer diameter 212and an inside retainer diameter 214, a first surface 216 between theoutside retainer diameter 212 and inside retainer diameter 214 closer tothe access surface 110 of the fixation plate 102 and a second surface218 between the outside retainer diameter 212 and inside retainerdiameter 214 closer to the bone facing surface 108 of the fixationplate. Changes in the inside retainer diameter of the retainer may ormay not alter the outside retainer diameter of the retainer, and viceversa. In some embodiments, the retainer ring or collar has a completelyclosed configuration, but in other embodiments, as shown in FIGS. 13A to13C, the ring or collar 200 has an interrupted configuration comprisingtwo ends 220, 222 about an expansion space 224. The retainer ring/collar200 is capable of radial expansion and collapse by altering the distancebetween the two ends 220, 222.

In one embodiment, the retainer ring 200 is configured to resilientlycollapse such that the outside retainer diameter 212 is less than thefirst diameter 166 of the flange hole 204 so that the retainer ring maybe passed into the flange hole recess 206. The retainer ring 200 canthen re-expand its outer retainer diameter 212 to at least partiallyoccupy the flange hole recess 206. The retainer ring 200 is furtherconfigured to resiliently expand its inside retainer diameter 214 toallow passage of a screw or anchor head 226 through the retainerring/collar 200. Expansion of the inside retainer diameter 214 may ormay not result in expansion of the outside retainer diameter 212 tooccupy additional space within the flange hole recess. In someembodiments, the retainer ring/collar comprises a compressible ordeformable material such that the inside retainer diameter can beincreased without requiring increase in the outside retainer diameter.

By configuring the retainer ring/collar 200 to resiliently deform whenthe screw or anchor head 226 is passed through the retainer ring/collar200 with an increased force, the retainer ring/collar 200 can resistbackout of the screw 202 or anchor where the backout forces acting onthe screw 202 or anchor are insufficient to cause ring/collar 200expansion and allow movement of the screw 202 or anchor. The forcerequired to backout the screw or anchor may be increased relative to theforce required to pass the screw or anchor through the retainingring/collar by providing a ramped surface about the retainingring/collar and/or the screw or anchor head.

Referring to FIG. 14, a surface 228 about the inside retainer diameter214 of a ring/collar 230 that is ramped or inclined radially inwardtoward the bone contact surface 108 of the fixation plate 102 mayfacilitate the insertion of the screw 202 or anchor through the retainerring/collar while providing a larger second surface 232 of the screw oranchor to resist backout. Similarly, a screw or anchor head may alsohave a ramped or inclined surface radially outward from the screw bodythat may facilitate insertion of the screw or anchor through theretainer ring/collar while providing a larger screw or anchor headsurface area to resist backout.

The cross sectional shape of the retainer structure may be any of avariety shapes, including a circle, oval, squares, rectangles, polygonalor other closed shape. The cross sectional shape of the retainer mayvary along the length of the retainer. The cross sectional shape of thescrew hole indentations may also be any of a variety of shapes,including a circle, oval, squares, rectangles, polygonal or other closedshape. The cross sectional shape of the retainer along the outsidediameter may or may not be similar to the cross sectional shape of thescrew hole circumferential indentation or recess.

In one embodiment of the invention, shown in FIGS. 13B and 13C, theimplant further comprises an flange hole insert 234 that provides anintermediate layer of material between the screw or anchor head 226 andthe inner surface 236 of the flange hole 204. The insert 234 maycomprise a generally polymer, metallic, or ceramic member comprising anouter flange hole contacting surface 238 and an inner anchor contactingsurface 240, where the outer flange hole contacting surface 238 isshaped to conform to at least a portion about the inner surface 236 ofthe flange hole 204. The anchor contacting surface 240 may or may notconform to at least a portion of the screw or anchor head surface 242.In one embodiment of the invention, the flange hole insert 234 iscapable of absorbing wear forces transmitted between the fixation plate102 and the screw 204 or anchor. Absorption of the forces between thesetwo components of the implant may reduce the risk of implant failureand/or loosening that occurs at the interface between the twocomponents.

In one preferred embodiment, the flanged interbody device comprises apolyaryl polymer, including but not limited to PEK, PEEK, PEKK, PEKEKKor a blend thereof, and the insert comprises a titanium or titaniumalloy. Other combination may also be used as is known by those withskill in the art.

3. Complementary Flange Configurations

In one preferred embodiment, the flange is configured for positioningacross an intervertebral space such that the upper portion of the flangeis adapted to contact the superior vertebra and the lower portion of theflange is adapted to contact the inferior vertebra about anintervertebral space. In other embodiments, the flange may be configuredto contact a single vertebra about an intervertebral space, or more thantwo vertebrae. In some embodiments, the flange may span two or moreintervertebral spaces. Typically, the implant is adapted for positioningabout the anterior surface of the vertebrae, along the anterior surfacesof vertebral bodies. In some instances, the flange of the implant mayalso be configured to contact other vertebral structures such as thepedicles, transverse processes, facet joints, superior and inferiorarticular processes and spinous processes. In still other embodiments,the implant is configured to attach to these vertebral structureswithout attaching or contacting the vertebral bodies.

In one embodiment of the invention, illustrated in FIGS. 5A through 5C,the flange 102 of implant 100 has a general square or rectangular shapeand is dimensioned to allow stable attachment of the implant 100 to theadjacent vertebral bodies 8. The corners where any two sides of theflange meet may be angled, rounded or curved. The flanged implant 100depicted in FIGS. 5A through 5C comprises rounded corners. In otherembodiments, the flange 102 may comprise any of a variety of othershapes, including trapezoids, circles, ovals, polygons or other closedshapes. The flange 102 may or may not have a symmetrical configurationwith respect the upper and lower portions and/or the left and rightportions of the flange.

Depending upon the location of implantation, the shape and/or dimensionsof the flange may or may not allow implantation of the additionalimplants at adjacent intervertebral spaces. In some embodiments,depicted in FIGS. 15A and 15B, the flange 244 of one implant 246 isconfigured and dimensioned to form a complementary shape with acorresponding adjacent implant and/or to prevent overlap or mechanicalinterference with an adjacent implant 248. The complementary fit betweentwo adjacent implants may be loose or tight. The interface between thecorresponding flanges may be non-overlapping as depicted in FIGS. 15Aand 15B, or overlapping, as shown in FIGS. 25A and 25B. Thecomplementary flanges may be asymmetric or symmetric with respect to theleft and right portions of the flanges, and/or the upper and lowerportions. Thus, the flange may be configured such that the verticalorientation of the flange, whether used right-side up or upside-down,does not affect the complementary interfacing with adjacent flanges.

FIGS. 15A and 15B depict one embodiment of the invention comprising animplant system with a superior implant and an inferior implant. Theinferior portion 252 of the superior implant flange 244 has aright-sided asymmetry that is complementary to the correspondingleft-sided asymmetry of the superior portion 254 of the inferior implantflange 250. The complementary-shaped flanges allow implantation of thesuperior flange and inferior flange at adjacent intervertebral spacesthat would not otherwise allow implantation of traditionally shapedfixation plates. In other embodiments of the invention, the left/rightasymmetry of each implant in the fixation system may be opposite.Furthermore, in some embodiments, as shown in FIGS. 15A and 15B, thesuperior implant 246 and flange 244 is identical to inferior implant 248and flange 250 but is rotated 180 degrees.

In one embodiment of the invention, illustrated in FIGS. 16A and 16B,the fixation system may further comprise one or more middle flangeimplants 256, a superior end flange implant 246 and/or an inferior endflange implant 248. The superior flange implant 246 and inferior flangeimplant 248 may have configurations and/or dimensions that have agreater surface area than the middle flange implants because there isonly one implant, rather than two, adjacent to each of the end implants.This may provide and utilize the greater stability and securementavailable at the end implants 246, 248 compared to the middle implants256. The inferior portion 252 of the superior flange implant 246 mayhave a right-sided asymmetry that is complementary to the correspondingleft-sided asymmetry of the superior portion 258 of the middle implantflange 256. The inferior portion 260 of the middle flange 256 implantflange may have a right-sided asymmetry that is complementary to thecorresponding left-sided asymmetry of the superior portion 254 of theinferior flange implant 248. The complementary-shaped flanges allowimplantation of the superior, middle and inferior flanges at sequentialintervertebral spaces that would not otherwise allow implantation oftraditionally shaped fixation plates.

Referring to FIGS. 17A and 17B, in another embodiment of the invention,more than one middle flange implant is provided. In the particularembodiment shown in FIGS. 17A and 17B, the flange of each middle implant256 is configured similarly, such that the superior portion 258 of eachmiddle flange implant 256 is complementary to the inferior portion 260of each middle flange implant 256, as well as the inferior portion 252of superior flange implant 246.

In some embodiments of the invention, a fixation system with serialimplants of different widths is provided. As shown in FIG. 18, eachimplant comprises a left/right complementary configuration as previouslydescribed, but implants 256, 262, 264 and 266 having differentleft/right widths are provided. The different widths do not interferewith the complementary configurations of the implants 256, 262, 264, 266in the fixation system. Having implants with different widths allow theselection of differently dimensioned implants as the size of thevertebrae change along a sequential length of the vertebral column.Furthermore, as illustrated in FIG. 18, the different widths of implantsneed not increase or decrease incrementally along the implantationsequence and may also allow tailoring of a particular implant to aparticular vertebral anatomy along a sequence of vertebral implants. Thedifferences in width of each implant need not be symmetrical withrespect to the left and right sides. Spacers of different left/rightwidths may also be provided. Spacer size need not correlate with changesin flange size or configuration.

Referring to FIG. 19, implants 256, 268, 270, 272 of different heightsmay also be provided in some embodiments to compensate for changes insize of lower vertebrae and/or pathological changes in height. Implantsof different heights may also have different widths.

Referring to FIG. 20, in another embodiment of the invention, eachimplant 268 of the fixation system has a superior flange portion that iscomplementary with the inferior flange portion of each implant withoutparticular superior end and inferior end implants.

FIGS. 21 through 23 depict embodiments of the invention where thesuperior and inferior portions of each implant flange in the fixationsystem are not complementary in a left/right manner, but each implantflange overall is complementary in a left/right manner. FIG. 21 depictsa three implant fixation system comprising a right-sided superiorimplant 274, a left-sided middle implant 276, and a right-sided inferiorimplant 278. FIG. 22 depicts a four implant fixation system comprising aright-sided superior implant 274, a left-sided middle implant 276, and aright-sided middle implant 278 and a left-sided inferior implant 278. Insome instances, the left-sided middle implant 276 and right-sided middleimplant 278 differs only by a 180-degree rotation. FIG. 23 represents afive implant fixation system comprising a left-sided superior implant274, two right-sided middle implants 276, one left-sided middle implant278 and a right-sided inferior implant 248. Likewise, six or moreimplants may be similarly configured and sequentially implanted.

FIGS. 24 and 25A and 25B depict embodiments of the invention where theflange is configured to allow sequential implantation along thevertebral column but the flange and flange holes maintain a left/rightsymmetry. In one embodiment, it is hypothesized that maintainingleft/right symmetry may reduce the torsional strain or stress actingupon the implants relative to the asymmetric implants describedelsewhere in this application. Flanges with left/right symmetry,however, are not bound by this theory. FIG. 24 depicts one embodiment ofthe invention where the upper portions 280, 282 of the middle andinferior implant flanges 284, 286 have a bilateral configuration whilethe inferior portions 288, 290 of the middle and superior implantflanges 284 have a medial configuration. Although the embodiment shownin FIG. 24 comprises a superior end and inferior end implants 292, 286,neither implant 292, 286 is necessary for the invention.

FIGS. 25A and 25B illustrate one embodiment of the invention comprisingimplants 294, 296, 298 with complementary overlapping flange shapes.Here, the superior portions 300, 302 of the middle and inferior implants296, 298 have an anterior configuration while the inferior portions 304,306 of the middle and superior implants 296, 294 have a posteriororientation.

C. IMPLANTATION PROCEDURE

In one embodiment of the invention, the patient is intubated and generalanesthesia is achieved. The patient is prepped and draped in the usualsterile fashion. An anterior approach to the spine is used to expose theanterior vertebral bodies. Many anterior approaches to the vertebralcolumn are described in various medical texts such as Campbell'sOperative Orthopaedics, 10th ed., edited by Canale et al., pp.1569-1588, herein incorporated by reference. In one embodiment, theupper cervical spine is accessed. The anterior upper cervical spine mayby a transoral or retropharyngeal route, or by using a subtotal orextended maxillotomy. In other embodiments, the lower cervical spine,cervicothoracic junction, thoracic spine, thoracolumbar junction, lumbarregion, lumbosacral junction, sacrum or combination of the above regionsare accessed.

The intervertebral space is debrided. The flanged interbody implant isoptionally packed with natural or artificial bone matrix and/or otherosteogenesis factors and inserted into the intervertebral space. Theflange is positioned against the anterior cervical vertebral bodies andattached with screws or anchors. The operative site is irrigated withantibiotics and the operative field is sutured closed. The vertebralcolumn is accessed and one or more intervertebral spaces are identifiedand accessed. In some embodiments, two or more intervertebral spaces areaccessed, and in still other embodiments, two or more adjacentintervertebral spaces are accessed. The operative site is rinsed withantibiotic solution and the operative field is closed in layers.

In another embodiment, the invention comprises the steps of providing anintervertebral implant system comprising a first fixation plate andfirst spacer and a second fixation plate and spacer, wherein the lowerportion of the first fixation plate has a complementary shape to acorresponding complementary shape at the upper portion of the secondfixation plate.

D. PIVOT PLATE

In another embodiment of the invention, the interbody spacer and thefixation plate are configured to provide some degree of relativemovement between each other. By providing some relative movement betweenthe interbody spacer and fixation plate portions, the device may haveimproved securement to osseous structures with improved conformance tothe existing anatomy at the site of implantation. FIGS. 26A through 26Ddepict one such embodiment, comprising a hinge joint 308 oriented toallow pivoting in the sagittal plane. In other embodiments of theinvention, the hinge joint 308 may be oriented to allow pivoting inother planes such as the transverse plane, coronal plane, or any planein between the three planes. The joint provided between the interbodyspacer 114 and the fixation plate 102 may be further configured to limitthe range of movement provided. In other embodiments, the configurationof the interbody spacer 114 and/or fixation plate 102 may restrict therelative range of motion between the two components. Recesses in thefixation plate 102 or a size reduction or tapering of the interbodyspacer component 114 about the movement joint 308 may allow greatermovement. One of skill in the art will understand that the movementjoint 308 may be configured to vary other characteristics of themovement joint, including frictional resistance or ratchet-typeresistance to movement. Although the hinge joint in FIGS. 26A to 26D aredepicted in a symmetric position on the interbody space and fixationplate, an eccentric location may be used. Moreover, although a singleinterbody spacer 114, fixation plate 102 and movement joint 308 aredepicted, other embodiments will have two or more movement joints 308and wherein either the fixation plate 102 and/or interbody spacer 114may have a split configuration so that each split component has its ownmovement joint 308 and can independently move or pivot to provideadditional conformance to the existing anatomy. In still otherembodiments, the fixation plate 102 and/or interbody spacer 114 may beconfigured with two or more subcomponents that are provided with anintracomponent hinge or movement joint to provide better conformance ofthe device to the existing anatomy. For example, the fixation platecomponent of the device may be configured as left and rightsubcomponents with a hinge joint in between. In another example, theinterbody spacer may have superior and inferior subcomponents with ahinge joint therebetween to allow pivoting of the superior and inferiorsurfaces of the interbody spacer. Depending on the orientation of thehinge joint, the superior and inferior surfaces of the interbody spacermay pivot laterally or in an anterior-posterior direction, or anydirection in between.

Although a hinge-type movement joint is depicted in FIGS. 26A to 26D,other types of joints or connections between the interbody spacercomponent and fixation plate are also contemplated, including but notlimited to a ball-and-socket joint or one or more metallic cordsembedded or attached between the fixation plate and interbody spacer toallow limited polyaxial movement.

E. ALTERNATIVE SCREW LOCKS

In addition to the embodiments of the screw retaining assembliesdescribed above, other screw retaining assemblies are also contemplatedand may be used with the interbody fusion devices previously described.The other screw retaining assemblies described below may also be usedwith other types of orthopedic and medical devices, as well asnon-medical applications, including but not limited to construction,home improvement, consumer appliance, electronic device and otherapplications.

1. Screw Retainer with Pivot Surface

FIGS. 27 and 28 depict an alternative embodiment of the inventioncomprising an expandable fastener retaining ring 310 residing partiallywithin an expansion groove 312 of a fastener lumen 112 and partiallywithin the fastener lumen 112 itself. The retaining ring 310 has areduced configuration and an expanded configuration but is biased to thereduced configuration. The retaining ring 310 has a retaining segment314 and a pivot segment 316. Referring to FIG. 28, the retaining segment314 has an enlarged outer diameter that is adapted to fit in anexpansion groove 312. In the expanded configuration of the retainingring 310, the retaining segment 314 further expands into the expansiongroove 312, thereby increasing the inner diameter 318 of the retainingsegment 314. The inner diameter 318 of the retaining segment 318 has asloped inner surface 320 that narrows from the proximal opening 322 ofthe retaining ring 310. The sloped surface 320 facilitates expansion ofthe retaining segment 314 as a fastener 158 is inserted through it. Oncethe fastener head 160 has passed through the retaining segment 314 ofthe retaining ring 310, the inner diameter 324 of the polyaxial segment316 of the retaining ring 310 is larger, allowing the fastener head 160to reside in the retaining ring 310 without exerting an expansion forceagainst the retaining ring 310. This allows the retaining ring 310 to atleast partially, if not completely, revert back to its reducedconfiguration. If backout forces are exerted on the fastener head 160,the fastener head 160 will abut a generally perpendicular retainingsurface 232 located at the transition from the inner diameters 318, 324of the retaining and polyaxial segments 314, 316 of the ring 310 andwill resist fastener head 160 backout.

The polyaxial segment 316 of the retaining ring 310 comprises a slopingreduced diameter 326 towards the distal opening 328 of the retainingring 310, such that the smallest diameter of the polyaxial segment 316is smaller than the largest diameter of the fastener head 160 andprevents or resists the fastener head 160 from passing completelythrough the retaining ring 310. The slope of the cross-section throughthe retaining ring may be linear, curved, toothed or jagged or any othersloped surface.

2. Fastener Head Embedded Expansion Lock

In another embodiment of the invention, illustrated in FIGS. 29A and29B, the fastener 330 comprises a secondary screw 332 and screw lumen334 within the fastener head 336. An expandable ring 338 or disc, havinga reduced and an expanded configuration, is provided within a groove 340about the fastener head 336, with the expandable ring or disc biased tothe reduced configuration. The groove 340 is contiguous with screw lumen334 of the fastener head 336 at one or more openings 342, such that theportion 344 of the inner surface 346 of the expandable ring 338 or discpartially protrudes into the screw lumen 334 when the expandable ring338 or disc is in the reduced configuration. The secondary screw 332 ofthe fastener 330 has an expansion section, typically the head 348 of thesecondary screw 332, which has an outer diameter 350 that is greaterthan the distance 352 within the screw lumen 334 where the expansionring 338 or disc protrudes into the screw lumen 334. When the expansionsection 348 of the secondary screw 332 is not in contact with the innerprotruding portions 344 of the expandable ring 338 or disc, theexpandable ring 338 or disc is able to remain in the reducedconfiguration. When the expansion section 348 of the secondary screw 332is fully positioned against the protruding portions 344 of theexpandable ring 338 or disc, it acts against the expandable ring 338 ordisc and causes the expandable ring 338 or disc to enlarge to itsexpanded configuration. In the expanded configuration, the outerdiameter 354 of the expandable ring 338 or disc is greater than thelargest outer diameter of the remaining portions of the fastener 330. Inthe reduced configuration, the outer diameter of expandable ring or discmay or may not radially extend from out of the groove.

Referring to FIG. 37, the fastener 330 is preferably used in deviceshaving one or more fastener lumens 356 with a proximal diameter 358,middle diameter 360 and distal diameter 362, wherein the proximaldiameter 358 is greater than the distal diameter 362 but less than themiddle diameter 360, and wherein the proximal diameter 358 is less thanthe outer diameter 364 of the expandable ring 354 or disc in the reducedconfiguration. The outer diameter of the expandable ring 338 or disc, inthe expanded configuration, is larger than the proximal diameter 358 ofthe fastener lumen 356, thereby preventing or resisting backout of thefastener 330. In other embodiments, as shown in FIG. 29A, the screwlumen may be lined by an hole insert 366 having a similar relationshipof its proximal, middle and distal diameters. A hole insert 366 may bepreferred, for example, when the orthopedic device utilizing thefastener system comprises a material that may exhibit wear from themetallic fasteners. A hole insert 366 may be provided to protect againstsuch wear.

Referring again to FIG. 29A, the screw lumen 334 of the fastener 330typically but is not required to extend distally from the openings 342contiguous with the fastener head groove 340 to allow the secondaryscrew 332 to completely reside within the screw lumen 334 in a positiondistal to the screw lumen openings 342 and inner protrusions 344 of theexpandable ring 338 or disc. This allows the fastener 330 to be attachedto the desired structure without having to later insert the secondaryscrew 332 into the fastener 330 to enlarge the expandable ring 338 ordisc. Instead, once the fastener 330 is attached to the desiredstructure, the secondary screw 332 need only be moved proximally in thescrew lumen 334 to act against the expandable ring 338 or disc andenlarge the expandable ring 338 or disc to its expanded configurationand to retain the fastener in place. By allowing the attachment of thefastener 330 with the secondary screw 332 already in place, the use offastener 330 in cramped or limited access areas, such as the attachmentof a cervical fusion plate or interbody fusion device, need not attemptto maintain a tiny secondary screw 332 on the end of an attachmentdevice while attempting to align the tiny secondary screw 332 with thescrew lumen 334 of the fastener head. The user of the fastener 330 onlyhas to align the screwdriver of the secondary screw to the secondaryscrew in order to manipulate it.

3. Side-Biased Screwhead Lock

In another embodiment of the invention, the screw retaining assemblycomprises a biased blocking body residing in an access space about afastener lumen. Referring to FIGS. 30A and 30B, the blocking body 368comprises a structure with a fixed opening 370 sized to allow passage ofa fastener 158. The blocking body 368 further comprises one or more biasmembers 372 that are biased to an uncompressed configuration in FIG.30A, but wherein the bias may be overcome to move the bias members 372to a compressed configuration as in FIG. 30B. FIG. 31 illustrates theblocking body 368 in FIGS. 30A and 30B located about a fastener lumen112 in the uncompressed configuration. In FIGS. 32A to 32C, the blockingbody 368 has a first position within an access space 374 that allowspassage of a fastener body 162 through the opening 370 in the blockingbody 368. The opening 370 of the blocking body 368 preferably has anarrowing sloped surface 376 from its proximal face 378 toward itsdistal face 380 to facilitate the displacement of the blocking body 368to its compressed configuration as the fastener head 160 is insertedinto the opening 370 of the blocking body 368. FIGS. 33A to 33Cillustrate a second position of the blocking body 368 within the accessspace 374 that prevents or resists passage of the fastener head 160 pastthe blocking body 368.

Although the embodiments of the invention depicted in FIGS. 30A to 33Cillustrate a blocking body 368 comprising a generally looped structure,one of skill in the art will understand that only a portion of the loopserves a blocking function, and therefore, in other embodiments of theinvention, the blocking body may be a partial loop, or any other shapedstructure configured to protrude into the fastener lumen 112 orpassageway in an uncompressed configuration and not protrude into thefastener lumen 112 or passageway in the compressed configuration. Theblocking body 368 need not be curved or looped. Furthermore, althoughthe bias members 372 depicted FIGS. 30A to 33C are attached to theblocking body 368, one of skill in the art will understand that the biasstructures used to bias the blocking body to its second position neednot be attached to the blocking body. Instead, the bias structures maybe attached to one of more surfaces of the access space, or reside inthe access space but is not attached to any structure. For example, theaccess space may contain a separate blocking body and bias structure,such as a helical or leaf spring, that exerts an expansion force betweena surface of the access space and blocking body to bias the blockingbody in the second position.

4. Lock Plate

In another embodiment of the invention, some embodiments of the flangedinterbody fusion device 382 may comprise locking plates 384 that may beattached to the fixation plate 102 to overlie at least portion of one ormore bone screws 158 or fastener heads 160 to prevent or resist backout.FIGS. 34A and 34B represent one embodiment of the invention with anX-shaped locking plate 384 attachable to the fixation plate 102 using afastener 386. Other locking plate configurations may also be used,depending on the particular arrangement and number of the bone screwsused to fasten the device to the bone. As shown in FIG. 34B, the lockingplate 384 may comprise one or more alignment structures 388 that preventthe locking plate 384 from spinning as the fastener 386, typically ascrew, is rotated to engage the locking plate 384 to the fixation plate102. The alignment structures typically but not necessarily willinterface with complementary structures on the fixation plate 102. Inother embodiments, a fastener may not be required as the alignmentstructures or other portions of the fastener may form a snap fit withthe fixation plate 102.

As depicted in FIGS. 35A and 35B, more than one locking plate 390 may beused. As shown in FIGS. 36A and 36B, the locking plates 392 may beangled or otherwise shaped for a particular fixation plateconfiguration.

F. CONCLUSION

Although the present invention has been described in relation to variousexemplary embodiments, various additional embodiments and alterations tothe described embodiments are contemplated within the scope of theinvention. Thus, no part of the foregoing description should beinterpreted to limit the scope of the invention as set forth in thefollowing claims. For all of the embodiments described above, the stepsof the methods need not be performed sequentially.

What is claimed is:
 1. An implant system for treating the spine,comprising: a first stabilization plate comprising: a first accesssurface and a first bone facing surface; a first attachment lumenbetween the first access surface and the first bone facing surface, thefirst attachment lumen disposed on a lower portion of the firststabilization plate; a second attachment lumen between the first accesssurface and the first bone facing surface, the second attachment lumendisposed on an upper portion of the first stabilization plate; and afeature configured to prevent an anchor from backing out of the firstattachment lumen, the feature configured to be located within the firstattachment lumen; wherein the lower portion of the first stabilizationplate is offset to a first side and the upper portion of the firststabilization plate is offset to a second side that is opposite to thefirst side.
 2. The implant system for treating the spine as in claim 1,wherein the feature is a first retaining ring.
 3. The implant system fortreating the spine as in claim 1, wherein the feature is a firstretaining ring configured to be positioned within a first recess,wherein the first recess is located between the first access surface andthe first bone facing surface.
 4. The implant system for treating thespine as in claim 1, wherein the feature is an expandable memberconfigured to be located at least partially within a groove of ananchor.
 5. The implant system for treating the spine as in claim 4,further comprising an internal screw comprising a screw body and a screwhead, the internal screw having a proximal position and a distalposition, wherein, in the distal position, the screw head is locateddistal to the groove such that the expandable member is in a reducedconfiguration and, when rotated from said distal position to theproximal position, the screw head is located about the groove anddisplaces the expandable member into an expanded configuration.
 6. Theimplant system for treating the spine as in claim 1, further comprisinga second stabilization plate comprising: a second access surface and asecond bone facing surface; a third attachment lumen between the secondaccess surface and the second bone facing surface, the third attachmentlumen disposed on a lower portion of the second stabilization plate; anda fourth attachment lumen between the second access surface and thesecond bone facing surface, the fourth attachment lumen disposed on anupper portion of the second stabilization plate; wherein the lowerportion of the second stabilization plate is offset to a first side andthe upper portion of the second stabilization plate is offset to asecond side that is opposite to the first side; wherein the lowerportion of the first stabilization plate has a configurationcomplementary to the configuration of the upper portion of the secondstabilization plate.
 7. The implant system for treating the spine as inclaim 1, further comprising a spacer extending from the first bonefacing surface.
 8. The implant system for treating the spine as in claim1, wherein the first stabilization plate comprises a flange configuredto form a complementary shape with a second stabilization plate.
 9. Theimplant system for treating the spine as in claim 8, wherein the flangecomprises the first attachment lumen.
 10. An implant system for treatingthe spine, comprising: a first stabilization plate comprising: a firstaccess surface and a first bone facing surface; a first attachment lumenbetween the first access surface and the first bone facing surface, thefirst attachment lumen disposed on a lower portion of the firststabilization plate; a second attachment lumen between the first accesssurface and the first bone facing surface, the second attachment lumendisposed on an upper portion of the first stabilization plate; and afirst retaining ring configured to be located within the firstattachment lumen between the first access surface and the first bonefacing surface, wherein the first retaining ring is configured toprevent an anchor from backing out of the first attachment lumen;wherein the lower portion of the first stabilization plate is offset toa first side and the upper portion of the first stabilization plate isoffset to a second side that is opposite to the first side.
 11. Theimplant system for treating the spine as in claim 10, wherein the firstretaining ring is configured to be positioned within a first recess,wherein the first recess is located between the first access surface andthe first bone facing surface.
 12. The implant system for treating thespine as in claim 10, further comprising a second stabilization platecomprising: a second access surface and a second bone facing surface; athird attachment lumen between the second access surface and the secondbone facing surface, the third attachment lumen disposed on a lowerportion of the second stabilization plate; and a fourth attachment lumenbetween the second access surface and the second bone facing surface,the fourth attachment lumen disposed on an upper portion of the secondstabilization plate; wherein the lower portion of the secondstabilization plate is offset to a first side and the upper portion ofthe second stabilization plate is offset to a second side that isopposite to the first side; wherein the lower portion of the firststabilization plate has a configuration complementary to theconfiguration of the upper portion of the second stabilization plate.13. The implant system for treating the spine as in claim 12, furthercomprising a third retaining ring configured to be positioned within thethird attachment lumen between the second access surface and the secondbone facing surface, wherein the third retaining ring is configured toprevent an anchor from backing out of the third attachment lumen. 14.The implant system for treating the spine as in claim 10, furthercomprising a spacer extending from the first bone facing surface.
 15. Animplant system for treating the spine, comprising: a first stabilizationplate comprising: a first access surface and a first bone facingsurface; a first attachment lumen between the first access surface andthe first bone facing surface, the first attachment lumen disposed on alower portion of the first stabilization plate; and a second attachmentlumen between the first access surface and the first bone facingsurface, the second attachment lumen disposed on an upper portion of thefirst stabilization plate; wherein the lower portion of the firststabilization plate is offset to a first side and the upper portion ofthe first stabilization plate is offset to a second side that isopposite to the first side; an expandable member configured to belocated within the first attachment lumen and at least partially withina groove of an anchor, the expandable member configured to prevent theanchor from backing out of the first attachment lumen; an internal screwcomprising a screw body and a screw head, the internal screw having aproximal position and a distal position, wherein, in the distalposition, the screw head is located distal to the groove such that theexpandable member is in a reduced configuration and, when rotated fromsaid distal position to the proximal position, the screw head is locatedabout the groove and displaces the expandable member into an expandedconfiguration.
 16. The implant system for treating the spine as in claim15, further comprising the anchor, the anchor comprising a proximal headcomprising a central internal lumen, the groove contiguous with thecentral internal lumen.
 17. The implant system for treating the spine asin claim 15, wherein the screw body of the internal screw comprisesthreads.
 18. The implant system for treating the spine as in claim 15,wherein the screw head of the internal screw comprises an angled edge,wherein the angled edge displaces the expandable member into theexpanded configuration.
 19. The implant system for treating the spine asin claim 15, further comprising the anchor, wherein an outer diameter ofthe expandable member in the expanded configuration is greater than alargest outer diameter of the anchor.
 20. The implant system fortreating the spine as in claim 15, further comprising a spacer extendingfrom the first bone facing surface.